Yep! I use that with my personal 1password. And honestly, that's probably the way we'll go eventually, but right now we're a super tiny startup - setting up a team 1password and getting every new engineer onboarded seems like a hassle. Even if it's only a few hours of work, tfa.one seems like it's a few minutes of work. For non-sensitive accounts (which is the main pain point I have at the moment), a 1-step tool is awesome. :)
It prompts for some sites (using some .well-known URL protocol?). But I recently learned you can add the "One Time Password" field type to any Login entry manually. I do it all the time for intranet/test sites that need MFA and I have done it with sites that didn't prompt that are shared in our family (home) and team (work) 1Password vaults. The field time lets you scan a QR code or enter the seed key manually