It’s still emulation. Yes, it’s emulating hardware, as close as possible and often indistinguishably close, but it’s still emulation.
For example, my EDGB X7 runs fine on any real Game Boy I have, but can’t switch games on an Analogue Pocket.
Another weird issue that I had was that if I launched my Pokemon Crystal save on Pocket it would, for some reason, permanently change my character from a boy into a girl (without saving the game!). This wasn’t happening on my Game Boys (I restored the save a couple of times to test it).
It is not emulation, it is hardware replication. And yes it is not always perfect. As with any replicated or cloned hardware it is just as good as the available information and the skill of the manufacturer.