With a permanent residence permit in Ukraine you can do a lot:
You won't need to renew this residence permit every year. Once it is issued it remains valid forever!
Your close relatives will also be able to apply for permanent residence in Ukraine.
Officially work in Ukraine. You will no longer need to receive any additional permissions.
Get customs clearance for your car at a zero rate.
This is an obligatory and the most important step on the way to Ukrainian citizenship.
You will be considered a full-fledged resident of Ukraine. And you will pay the same taxes as citizens of Ukraine do