I'm not going to lie, I DID pick up a fidget spinner some time ago and DID find some intrigue in the way it spun.
I can see the appeal, at least from a sort of 'customizable' standpoint; I've seen custom-designed Fidget Spinners, and as an artistic person that likes to make things, this naturally clicks with me. Not to mention, the whole 'spinning' aspect reminds me of the good old days of Beyblades and invokes some heavy nostalgia for the Ninjago Spinners.
I guess it's a neat little thing to keep on hand and, well, FIDGET with, as the name implies, kind of like twiddling your thumbs while waiting. I don't really see the problem so long as it does not take away our appreciation for high quality entertainment and whatnot. I imagine if I invested the time, I imagine I could get an intrigue in Fidget Spinners, all while appreciating Bionicle, Fullmetal Alchemist and its philosophies, drawing, reading and writing, and so forth.
All in all, I don't really see the problem and can empathize with the appeal. At worst for me it's a fun little joke to make a jab at, but otherwise, I'm perfectly fine with letting the trend pass by. Besides, we've got worse problems today, anyhow.