Topic drift, but no tools should use google login. Doing that means handing over to google the authority to decide who can and can't use your tool. And we all know google support is nonexistent and unreachable, so once it fails it's forever.
If you market a tool, you'd really want to own the decision on who you can sell it to.
For a government organization though, I'd agree it makes sense to use a government-run login service. (government run, not outsourced so some for-profit third party!)