If it can emulate x86, is there really a motivation for developers to switch to ARM? (I don't have an M1 and don't really know what it's like to compile stuff and deploy it to "the cloud.")
Sure, but as a counter example Docker performance on Mac has historically been abysmal[0][1], but everyone on Mac I know still develops using it. We ignore the performance hit on dev machines, knowing it won't affect prod (Linux servers).
I don't see why this pattern would fail to hold, but am open to new perspectives.
The VM that uses takes advantage of hardware-accelerated virtualization, for running amd64 VMs on amd64 CPUs. You don't have hardware-accelerated virtualization for amd64 VMs on any ARM CPUs I know of...