I suppose for folks here, they like being able to do dev work (as well as web browsing) on a fast laptop with low power draw. Sounds like that's not exactly your use case.
To add a bit (I wrote this in response to a deleted comment):
The yocto build I'm currently working on takes about six hours to complete on my biggest machine. Yes, it's an incremental build, but warming up a laptop would require several days of 100% CPU :)
It's also not really possible to test locally, even a VM of the right architecture is insufficient without doing a bunch of work to make it match the target hardware.
Often you can build a quick little ad hoc thing that lets you test some piece of it locally, but sometimes it's too much work.
Frequently I need to compile test several dozen Linux kernel configurations with different cross compilers, each of which takes half an hour to run on the huge box.
I can't imagine doing any of this locally on a single laptop, I would get 1% as much done as I currently do.
