A laptop that is so beefy it can even run GLM 5.3 locally (while sounding like a jet engine, being as bulky as an old-school travelling briefcase, and having a 1.5 hour battery life) though?

GGP's point is just: keep the bulk of your compute at home, where airflow and energy is cheaper (in an opportunity-cost sense). Keep the laptop portable, cool, and light, with long battery life by offloading your own computing tasks to your own hardware.