The web accessibility world is complex enough that simulating different methods of access like using screen readers or different font-sizes and doing manual tests for compliance is not particularly feasible if you want to make your content accessible to all.
[1] https://developers.google.com/web/tools/lighthouse [2] https://web.dev/accessibility-scoring/
Interesting use of "blindly". Using lighthouse or other accessibility checkers is better than not considering accessibility at all, and has a much lower barrier for developers and development orgs than integrating screen readers into the development lifecycle.
I was in an org where our QA team actually used our sites with screen readers, and yet we still ran automated accessibility tests on our codebase. This is because we can catch issues earlier and more easily, and reduce the amount of issues making it to manual QA which is much more time consuming and expensive.
Manual QA testers using screenreaders are also not perfect and miss a lot of nuances :)