I agree with OP in that Sony hasn't done much to sell me on it. I don't think the uptake with be very big due to the lukewarm reception and lack of compelling reasons to upgrade right now, but at the same time, like OP, the vague promise of better performing games will be enough to get a good amount of people taking the leap, even if they don't get everything they'd expect.
I think that is why Sony is staying tight lipped, because while it wouldn't be true to say only people will a 4K TV benefit from it, they can let people assume things like checkerboard upscaling and HDR is some secret sauce that will make everything better on 1080p TVs. In fact, I've seen enough people on GAF with these exact assumptions and this is a forum where people would supposedly know and care about spec stuff like this.