They've never really been my thing, mostly because I've already got a bunch of random stuff to mess around with when I feel the need. Dice, mechanical pencils, game systems that aren't turned on...pretty much the only things I haven't used as fidget toys are actual fidget toys, which amuses me a bit.
Also it will never not be hilarious to me that, just as fidget spinners were at the height of their popularity as a fad toy, Cygames added a fidget spinner-themed character to Granblue Fantasy