I think I was slightly less than that but yes it's really useful. If you click on a match there is a page which lists all the shared matches you have with them and what estimated relationship and cM value you are to them and what their estimated relationship and cM value is to the shared match.
This means you can see that Dorothy Jones is Fred Smith's aunt. If Dorothy Jones doesn't have a tree but Fred Smith does, it gives you a good idea where Dorothy Jones might fit in.
So any matches you get through thrulines (or your own research) and have placed into your tree you can then work through and see how they fit with your shared matches.
I've managed to get a good hundred or so matches into my parents / DHs family trees just from using this.
It's helped me identify most of the close matches my Dad and DH have. I've got a fair way with my Mum's too but still struggling with the Irish side. I have worked out a couple of family names my Mum MUST be directly related to, I just can't definitely prove the link, which is frustrating.
But it's not cheap. I think you have to be at that stage of wanting to take it to the next level and match up either a specific person or want to work out all your matches. If you are just doing it casually it's not worth it.
I believe there's a big ancestry update imminent - which does change some of the % estimates of your origins (rumour is it's next month). So your origin profile can and does change occasionally when they do an update. Your DNA hasn't changed but their interpretation has. I believe they are adding a specific Cornwall area origin in this upcoming update and they are separating Sweden/Denmark and refining German origins. This is done as they gain more data and have better information about shared DNA. (The same is true of other DNA sites).