Yeah, they're cool. I first saw them in Games Workshop stuff in the 90s. Very handy if you're just using d6s, in particular.
Oh yeah, I love 'em. With
@Reynard's suggestion of a table of professions/background skills, I'd probably go with d66 just to get more options in there, with more "common" or widely applicable backgrounds/skills at the table entries with 16.6% chances like 61, 52, 43, 34, 25, and 16, etc.
You say you don't want to use the system for bribing the guard or rolling perception, but you don't say what you do want to use it for. What sorts of skills, used under what circumstances, are you thinking of?
Broadly, though, using the Turn matrix as the foundation for a general difficulty chart isn't a bad idea.
To get back to the idea of using the Turn Undead matrix as a difficulty chart, I have two questions I'm mulling over...
1) How much guidance does a GM (ok, it's me) need to distinguish a Level 1 lock from a Level 5 lock for purposes of lockpicking? With monsters, Hit Dice makes it clear. In a megadungeon, dungeon levels can work. The chart can be adapted to use damage instead, eg. 1d6 damage per level, so a level 5 challenge would be 5d6 (avg 17 damage), which might work for checks involving falling or even traps or falling damage. But there are plenty of situations that don't conform to these neat numbers, like lockpicking.
2) Is the whole "if the challenge is 3+ levels higher than your level, you just cannot" stipulation natural and useful? Or does it feel like the GM arbitrarily setting a "you must be 5 feet tall for this ride" requirement.
