That is indeed what it is for! When you 'BUMP' a thread it goes back to the top spot on the first page of the board so more people can see it. You'll have to check individual board rules to find out what threads you may BUMP when... All I know is that on thr Re-Tail board it's once every 4 hours.
It's especially helpful in crowded threads, like when you're having an art shop, and you're not updating as often.
You can easily find your thread without needing to flip some pages to find it.