I know what a PoE is meant to do but what is it actually for does it help in the use of motors or does it run the board more efficently what is its niche?
A little more context is probably necessary.
PoE, to me, stands for power-over-ethernet, but that doesn't seem to fit your question.
PoE, as in Power Over Ethernet, is basically for running remote devices/sensors without needing to run power.
So, a large office/college would set up a PoE system to power all of their wireless access points (wifi receivers on the walls) because they would only need to run a single ethernet cable to each spot instead of hiring an electrician to run 120v power everywhere.
In a Arduino perspective, it allows you to have remote sensor arrays set up all over the place and only need to run one thin Cat5 cable to them as opposed to a fat 120v feed, and so on.
I wrote a little about using PoE on my blog.