Kas (this is your name, right?),

Sure. My full first name is "Kassen", and signing as "Kas" seems nicely informal.

I first learned about LiSa as a recorder. Which is why I didn't expect
things like the voices.
Then I learned that LiSa is more a flexible sample player than a recorder.

Yes, it stands for LIve SAmpling. You can look at it as a looper (as in guitar loopers) or a simple sampler or a granulation tool. The technique is a fairly classical computer music one.

Currently I am re-visiting the WvOut and WaveLoop ugens. At the
beginning when I didn't know much of chuck I made a silly mistake,
which made me think I couldn't use them for my purpose. But now I
found that they work well for me. LiSa is very nice for playing the
same sample in multiple ways (different frequency etc.), but for my
project it is a little oversized.

I think so, yes.

hmm, I don't think. Lisa's voices are special, no other ugens have them, right?

As I see it the core "special" thing here is UGen member functions taking two parameters and the extra convenience trick of being allowed to not specify the voice if you only need the first. As I see it the confusion arises from permitting that shortcut. Maybe that was a dubious choice but the convenience might be worth it? I don't know.

I agree...but then the shortcut isn't really needed.

No, not "needed" as such, but after writing some pages of code that makes ChucK look like a "scripting extension to LiSa" you come to appreciate it. :-)

You do have a point and as I mentioned; I ran into it too, once. It's a hard to detect mistake. One big question here is that I can't see a alternative that would be clearly better in all ways yet not break existing code. Tricky stuff.

Yours,
Kas.