A couple of things:

Yes hal, we can play YT videos on Kinoma; but not via the 'old way' (i.e. from the Kinoma Guide).

As for downloading (at least through Kinoma), that seemed to stop working before they stopped 'supporting' Kinoma EX for Palm. I stopped seeing the icon they used for that a long time ago. I wondered about that, but I never did anything about it, because I usually downloaded YT from a computer with Downloadhelper.

I'm pretty sure that Kinoma EX was meant to play Flash video from YouTube and even stored on the device. I don't think that works anymore. I'll have to play around with it more.

It seems like the Guide itself is no longer supported in some ways, although the lists of videos seem to be updated. But you can't play a video selected there. You have to go through Blazer, which then activates Kinoma (non embedded on my device).