They're not important, but we're also simple creatures who find it amusing when some numbers go up. And KPI's can also be fun for things like A/B testing etc. You could even rig something for some positive reinforcement to send a notification when a post is overperforming.

But I haven't found any analytics tools that strike the right balance; they either are too unwieldy, or they're absurdly simplistic.

These days, going viral is very much a double-edged sword, and getting a heads up is useful in more ways than one.