Well, when I say "tends toward" what I mean is if I have an average team of programmers, when I look through the code a year after the project starts, is this what I'm going to find?
I realize expert programmers can write legible code in any language, in the same way Tiger Woods can best me over 18 holes using only a five iron. But there are some languages, like C++, that tempt mediocre programmers into writing illegible code. That's a big strike against, IMO.
I doubt you'll have to worry about that specific problem with a team of average programmers. They won't be naming new functions with pure symbols, which is what that code represents. Just don't tell them Scala allows that and you should be fine. If they figure it out, outlaw it and require the use traditional descriptive English camelcase.
I realize expert programmers can write legible code in any language, in the same way Tiger Woods can best me over 18 holes using only a five iron. But there are some languages, like C++, that tempt mediocre programmers into writing illegible code. That's a big strike against, IMO.