You're right. I looked again and... it wasn't there. Turned out to be a real doozy:
You know how pasting creates this special "floating" layer? While in this mode, the "Layer->Merge Down" menu command is replaced by "Layer->Anchor Layer" - which has the keybind. "New Layer" also becomes "To New Layer".
While I can see how it makes sense on some level, it's also a whole new kind of counterintuitive.
Yeah, that's mostly my issue with it. IIUC it's no longer the default behavior in version 3, so good choice on the team's part.
The problem with it is that we've had a good UX understanding of how modal behavior works for ages, and if you're going to do something modal, you need to make clear to the user that the mode has changed (especially to the naive user, who has no reason to anticipate paste enters a novel mode). The indicators that mode has shifted are too subtle: one is the buttons going green on the layer panel (which I think can be hidden at that point? I'd have to check), and the other, I have now learned, is some menu options changed. No dialog box, color switch, or text indicator to say "PASTE MODE: choose how this pasted data should be added to the image."
And when it's so high on the critical path of using the software (how long does the average user use an image editor before they try to paste something?), it's a huge hit to the overall experience and makes the user feel like this tool is too complicated.
(Not sarcastic.)