Besides doing my taxes on paper, I can't think of anything more tedious than filling out tax forms via a vanilla HTML form.

At least my SPA tax software makes the form filling a little more exciting, and doesn't s#!t the bed when I hit enter by accident

Simple form validation would prevent that, not exactly SPA worthy.

Personally I wish more forms did have enter bound to submittal

A problem is, that I need to fiddle around with JS blocking, even on official websites from city, state or gov, because they hired inresponsible web devs or made inresponsible decisions to let Google and others track me on their website. So initially they will be blocked. As far as "experts" for SPA are concerned, they often do not even include a noscript tag, which means I see a white page. Now it cannot become less user friendly than that. I've yet to see a SPA, which offers a working alternative via noscript tag, when I blocked all their tracking. The thing is that SPA all too often serves as a way to force tracking onto the unsuspecting user. "You need to allow our JS! Your browser is outdated! Use Chrome!" and the unsophisticated person will think: "Oh well, lets just whitelist this page dammit!"

Mostly I want my forms to be reliable, that doesn't seem to be the case for many SPA's. Getting a blank page is a very common experience and much worse than a barely discernible delay submitting a form.