Mainly performance will take a hit. USB drives are also not really rated for consistent writes so you’ll find a USB dies quicker than a standard drive

A surface tablet can be booted with Linux.

However I really don’t think a laptop is a bad decision. I myself run a 14" Lenovo ThinkPad: https://amzn.eu/d/09sY8lt1

It’s honestly small and I use it as a “on call” machine when I leave the house. Thing is light so I barely notice it in my bag