> Wouldn't it have been more worth it to simply buy an M1 Mac or a Surface?
Yes, probably, but I would note that a cheap M1 Mac is 4x the annual cost you cited for the browser, and if the browser is 95% of what you use a laptop for, getting the same perf boost for 25% the cost sounds like a good value prop.
Granted, a laptop should last more than a year, but presumably it starts to show it's age in under four, whereas the remote browser can improve over time.