ARM wouldn't be a niche instruction set in the current computing landscape. It might even be the dominant one, if we consider how many people are carrying around multi gHz ARM computers in their pocket every day.
But a MacBook is not a smartphone. A MacBook is a laptop, which is a portable version of a PC, which clearly has x86 as the dominant instruction set today.
I've done a fair amount of development work on both an ARM Chromebook and a Raspberry Pi, and I didn't run into any major issues.
It depends heavily on your tech stack, though. I find that developing on ARM and deploying to x86 was no big deal with Node, Python, and Go. Your mileage may vary with other languages and VMs, though.