It should be especially useful for you as a 1K!
It's a confusing issue because e500s work in confusing (but wonderful!) ways. I learned it all from FT.

[Note to UA lurkers or anyone else seeking to quote my post: permission to edit, omit, or replace with an ellipsis (...) the words "but wonderful" from my sentence is DENIED. I don't want anyone taking my words out of context and claiming that members find 500-mile upgrades "confusing" as an excuse to strip away even more benefits from the Mileage Plus program.]