I guess the point is it shows how active someone is on a forum, to be honest i think it's just a standard feature built into all forum software i've never seen a forum that doesn't show post counts vBulletin,Invision they all show it.
I don't see any real reason to remove it personally.
I mean if post counts don't bother someone they don't need to take any notice of them i know i don't.
It is helpful for the Admin side of things though as the recent pruning shows there are a lot of zero post people registered some of which are no doubt sockpuppet accounts of banned members.