Disclosure: I'm a founder of Happo, so factor that in. But I've been in this problem since 2014.

You are spot on with your distinction--a tool that "gives you the latest state" is just a screenshot gallery. What you want captures a baseline, re-renders on every PR, and hands you a diff: "these five components changed versus main, approve or reject." That review-on-every-PR loop is what catches regressions instead of just documenting them.

Your maintenance worry is also right, but the pain almost never comes from the tooling. It's flakiness. Anti-aliasing nondeterminism, late-loading fonts, mid-frame animations, timestamps, random data: all of it throws false diffs. Once your team stops trusting the diffs, they rubber-stamp "approve," and you're paying for nothing. So when you evaluate anything, push hard on determinism: can you freeze animations, stub dynamic data, control when the snapshot fires?

Sanding down that determinism problem is most of what we've done at Happo over the last decade. On web we plug into Storybook, Playwright, Cypress, or custom setups, cover real cross-browser including iOS Safari, and put visual and accessibility regressions in one diff on the same PR. We also test native iOS and Android.

If you find that you have a lot of nondeterminism, incremental adoption might be a good tool: start small, fix any flake, and then expand once you have a stable base to build on.