I’m guessing you’ve never had a bag lost. Or had a holiday ruined when you arrived at your destination to discover that you only had the clothes you were standing up in for your two week vacation.
And no, it’s not that easy to pop into one local shop in a foreign country where you don’t speak the language / know the shops and replace the entire contents of your suitcase.
Especially if you have any specialty equipment for a diving / hiking / bird watching / photography / camping holiday.
And if the rest of your family / friends / group are all about to head off out of the city in a few hours.
And your insurers will only cover the cost of a few essential items until they are sure it’s lost / stolen and not just delayed.
Oh and did you know , they don’t cover the cost of replacing your items , just the costs of what you paid for them. So if you bought your narrow fit women’s hiking boots on sale for £100 in the Lake District 3 years ago, they will only give you that £100 minus depreciation, so perhaps £60. Which wont help if you have arrived in Iceland where you have to go to 5 shops to get narrow fitting ones and they costs £250.
Then multiply that by every item in your suitcase.
Are you taller / bigger than your average Asian person ? Oh dear, good luck finding new clothes, shoes and a new bra in many Asian counties, when you don’t know where to shop.
Even the smallest things can be a nightmare - where do you go for suncream without bleach in some countries ? Gosh the western brands are the equivalent of £20! Shame your insurers will only give you the £3 you paid Aldi.
Did I mention they won’t cover electrical items, like your laptop/ phone charger, adaptors, power bank, electric toothbrush , spare camera batteries and charger, hair styling items etc ?
And do you have proof of purchase for everything in your suitcase ? No I thought not. Tough luck then.
THATS WHY SOME PEOPLE DO CARRY ON ONLY.