Yeah, the "problem" with reduce is that it can do anything, and so doesn't offer much over a traditional for loop with mutable local variables to accumulate into. Of course, if you can replace a reduce() with a filter and/or map or whatever (which more clearly states intent), by all means do so!
If you really need arbitrary computation, I'm not sure there's any real readability benefit to reduce() over local mutation (emphasis on local!). Sure, there's immutability and possibly some benefit to that if you want to prove your code is correct, but that's usually pretty marginal.
