Viewfinder on Fuji x100T

I don't know why I can't wrap my head around the OVF and EVF on the Fuji x100t...I read up on it, watched a few videos on it, and I'm still just not getting it.
What's the difference in the 2, like when would you choose one over the other.....?

Anyone able to simplify it for this slow-learner?

I tend to just use the optical one, but I'm an old f*rt who probably doesn't appreciate what it can do

THIS LINK may help

I mostly use the EVF as I like the 100% view. I have some framing issues with the OVF. I also like the exposure preview with the EVF. I'll really only use the OVF to try to preserve the battery a little better.