I'd say that you're NOT crazy - that shot is definitely among the essentials in my toolbox, but I have to qualify my opinion. I grew up playing serve and volley tennis on grass courts, so I learned backspin shots right out of the gate. Slicing off both wings was a bread-and-butter essential for hitting good approach shots, but even though I've built a stronger baseline game, I still love my slice forehand.
The heavy topspin game with exchanges of loopy deep shots can freak some players out. Some hitters get pushed back by those high bouncers while others may try to hit some of those incoming loopy balls on the rise with a topspin reply - a more demanding shot, but it can be a solid alternative to letting those bounding balls back you up near the fence. Coaching high school kids has given me some perspective because slicing doesn't seem to be among the essentials for so many young (or even older) players these days. It can also be tricky business to teach it.
The drawback with the forehand slice is that it doesn't have as much zip as a decent topspin shot, so it can give a stronger player trouble if it's a low skidder, but it's not a shot that often travels through the court. Sure, consistency and accuracy rank quite high on the list of "stroke priorities", but better opponents may have much less trouble with this relatively slow shot.
In the same way that every player with either a one or two-handed topspin backhand should also learn a backhand slice, I believe that the same reasoning works with the forehand wing. The forehand slice is a strong option for returning serve, changing pace in a baseline rally, approaching the net, putting opponents at the net on the defensive (with a low shot)... blah, blah, blah. I suppose that my biggest problem with this shot is that it can be too much of a security blanket sometimes and I'll use it more than I should. I guess that's more of a tactics issue though, and not a problem with the shot itself.