Glimpse is useful for the chests you cant open. You can still learn what is in them. Not that useful but not completely useless.

Infiltrate is kind of crappy since you normally step out of hiding when you use it, which apparently you aren't meant to. But it can be done in combat. Pretty useless as you don't get the bonus good lockpicks would give you.

Lore of the ages is pretty useless. To improve it, I fought the svirf in lower cragstone that has the legendary hammer and pick. He still kicked my ass. But generally there's no one with magic legendary weapons, and other than that it doesn't seem to make a difference.

I, like you, screwed up the build and made a pickpocket thief who was friends with everyone so didn't steal from them. The places I most wanted to explore were beyond my abilities.