This is definitely a valid point, but the answer is not  
straightforward.  In your analysis, you question whether the benefits  
of learning a language outweigh the cost of doing so.  Unfortunately  
this can't be properly answered until after you've learned the  
language (see discussions of blub).

In the end, I think it comes down to how much the individual values  
knowledge for its own sake.  You have to be willing to invest time  
into something that may or may not be useful to you simply for the  
sake of learning it.

John L.

Quoting Mark Van Peteghem <Mark.Van.Peteghem@telenet.be>:

> Intrigued by that discussion about Haskell, I read quite a bit about
> it, and it looks like a very nice language. But I obeyed a rule in IT
> that says that when you can choose from a number of tools, you
> shouldn't only consider the features of the tools, but also which tool
> you (or your team) knows best. Learning a new tool may be interesting,
> but is also time consuming, especially if it is a very different way of
> doing things, like Haskell is.
>
> For CSound I'm just fine with Python, I don't see what Haskell could
> offer that makes things so much better that I can justify spending a
> lot of time on it. Actually I know C++ much better, but you can store
> Python code in a Blue project, a big plus, so I use Python.
>
> Mark