I'd submit that if I can't find a spot where my favorite trick solves a problem in a way that I can easily demonstrate is better than the existing alternatives, then my favorite trick is a solution in search of a problem.
I agree with everything you say except for the "easily" part. Sometimes you have to make a cognitive effort; said effort is by definition harder than not making the effort. But the payoff may be worthwhile!
I don't subscribe to the notion that for something to be worthwhile, it must be readily apparent and "easy" to understand. Especially in the context of FP, where most programmers -- but this is changing, thankfully! -- are traditionally trained in imperative languages, which means for them learning the FP "purist" mindset implies a significant effort.
My grandmother (R.I.P.) could never learn how to use an ATM. For her, using one was daunting and too much of an effort. It terrified her that she might make a mistake and push the wrong button. Back when she was young, ATMs didn't exist and she didn't need them. Her solution in modern days was to ask a helpful relative to use the ATM for her. Does this mean these hellish machines are "a solution in search of a problem"?
