At least on Bitwarden you can just edit the domain if that comes up a lot for you (or even add multiple domains to a password). I'd rather do that than copy/paste on a regular basis. Honestly I can't say I ever copy/paste.
Yeah, I do this too, but many people I know wouldn't even think about the fact that they could do that, or why they would. They just know that whatever password manager they use doesn't find the password but if they search for it, it's there. So they do that and get on with their lives, inadvertently opening up an avenue for phishing.