As all the earlier posters have said - a very definite yes. It can certainly help to confirm that you have the correct family.
Also, if you are tracing DNA matches, then that will definitely involve siblings of your direct ancestors.
However, most posters don't seem to have touched on your second question
"Has it thrown up anything of interest?"
I would very much agree with SwedishEdith and HelenaWilson that, quite often, it is the siblings of my ancestors (and their descendants) who have proved to have had more interesting lives.
I've posted on various threads here before about more distant relations. These relations have included quite a lot of people who have emigrated to various countries at various times. I'm sorry for repeating myself here.
For example, a number of my mum's older cousins were war brides. Just about every female member of my extended family that could grab herself a US soldier or airman in the 1940s and later the 1950s did just that and went off to the USA.
Then earlier in the 1900s I found someone who was forcibly emigrated from the UK at the age of 14 (he was in a workhouse) to go and work as an indentured servant on a farm in Canada. This happened to around 100,000 children from workhouses and orphanages in the UK. Many other relatives also emigrated to Australia, Canada and New Zealand in the 1800s and early 1900s.
Or if you have any male relatives born between about 1880 and 1900 then there is a reasonable probability that they served in World War One. This may not be so much of an interest but there is a great wealth of information available at The National Archives.
I found out quite a lot about relatives who served in both wars. One, who was captured by the Japanese in Singapore, recently had his portrait that was sketched at the time included in an exhibition.
Or older relatives may have served in earlier wars such as the Boer War or the Crimean War. A relative of mine drowned just after arriving in Crimea.
A relative joined the navy in the early 1900s and spent time sailing up and down the west coast of the Americas and saw President Teddy Roosevelt (who the 'teddy' bear was named after).
While in Chile, the ship obtained a young bear as a mascot. A midshipman on the same ship wrote
“Our bear is in a very flourishing state now. It is allowed to walk about the ship. Once it found its way down to an officer’s cabin on the Main deck. It eat his soap, gnawed his boots and finally went to sleep in his bunk. And today, an officer asleep in his cabin, woke up to find him eating his cigarettes by the hundred.”
He unfortunately died on the way home. His records say “D.D. [discharged dead] 17 Jan 05 in hospital at St Vincent, Cape Verdes from pneumonia”
Or going back earlier to the Mormons travelling to Utah. I found a few ancestors who followed the Mormon Trail to Utah in the 1850s and now I have dna relatives on both sides who live in Utah.
What really started this off for me though was when my mum got her DNA tested and she came across a whole load of very distant (5th to 8th cousins) DNA matches who had the same surname as her mother and they all lived in the USA.
How had that happened?
It turned out that the brother of my 8 times great grandfather (born 1636 in Gloucestershire) arrived in Maryland with one cow and an indentured servant and was granted 100 acres of land. He married and set up as a tanner, farmer and tobacco grower. By the time of his death he owned just over 500 acres of land.
His will included:
‘I do give and bequeath unto my brother John five thousand pounds of tobacco to be shipd home for Bristoll and consigned to him he paying the freight thereof the said tobacco to be sent the next shipping after my Decease.’
A cousin of his also later emigrated to Maryland as well. As it turned out, their descendants ended up fighting on both sides of the American War of Independence. One fought with the Delaware Regiment for the colonies and one fought for a North Carolina militia supporting the British. They even fought on opposite sides at the same battle in 1780.
But, sometimes, what you find can really make you stop and think.
For example, in the 1830 US Census, a branch of the family that had moved from Maryland to Georgia. They were a farming family aged 31 & 22 and had two young children. They also had two slaves; one was a male aged between 10 and 23 and the other was a girl under the age of 10 (those were the age categories in the census).
So it seems that they maybe had a teenage male slave to work on the farm and a young girl slave to help care for the children.
Then by the time of the 1840 census they had seven children and eight slaves. Two male slaves, presumably to work on the farm. There were also three adult female slaves and three girl slaves under the age of 10. I suppose they looked after the seven children of their owners.
When it came to 1850 the family now had eight children and 14 slaves. Although two of them had just been born. In the 1850 Census the sex and age of slaves were recorded, but not their names.
Just stop and think about that for a moment. Even in 1850 in certain states they are not even recording the names of slaves.
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I could really go on and on about the interesting stories of the siblings of my direct ancestors (and their descendents) - or, at least, what I find interesting.
Although most of them are just minor stories that I find interesting - such as one being a witness in a murder trial or another running her own business as a laundress and employing several people.
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In my experience, it is well worth while spending time exploring the lives of the siblings and their descendents.