It was a great feature and I was pleasantly surprised by it. Reusable TMs got rid of the idea of wasting a TM. Want your Scolipede to know Earthquake in-game but a Heracross to know it for competitive use? You can have both! Being able to use a TM for a good move multiple times felt great because that aspect of HMs felt wasted with some moves in the past (Whirlpool, Rock Smash, Cut). And the best part is that it's entirely optional. If you don't want to use a TM more than once, you don't have to.