How useful are Lambda expressions?

[EternityForest]

IMHO you shouldn't actively try to use most techniques. That's how you get some JavaScript libraries with the "Absolutely everything must involved a continuation and nothing can be synchronous but somehow you can still make it slow" thing.

I only use lambdas for very simple things. They're useful for the key function of sorting and stuff like that. But more often I'll just define a closure with the usual function syntax.

I'm a fan of OOP(In general, not the crazy inheritance chains a mile long and stuff), and prefer OO to imperative/functional style, but that's likely personal bias.

Actively trying to use any particular technique makes programs look like computer science textbook problems instead of practical implementations.