This feature I think started from them but these days, it's not only them that offers this but almost every exchange has got this now. It's a good way of introducing to the newbies and giving them some opportunity to earn a bit from the specific cryptos that will sponsor this feature.
I also think that websites like CMC and coingecko have this feature and if you're into grinding of earning from these, they're not really that much but it is a good way to spend your free time if you don't have a lot of things to do. Anyway, can also consider earning for free when you're like working actually and getting paid with crypto from the work that you do.