I like keyboards with layers support, but layers aren't a replacement for sufficient keys. Holding down the layer button means another finger unavailable for hotkeys. For instance, on my keyboard (ZSA Moonlander) I have the function keys in an alternate layer. This isn't a problem for a normal press (layer shift + 2 => F2), but it makes pressing something like Ctrl+Shift+F2 rather painful.
Yes, for such shortcuts that I use frequently I can create special custom keys in layers, but when using new apps or particularly complicated apps with lots of hotkeys (IntelliJ) that doesn't scale.