Not good enough, scammers will make copycat look-alike addresses that have the same first ~7 and last ~7 characters.

What about something like VisualHostKey but for the bitcoin address?

I doubt that would help much. People should clear their clipboard, and copy & paste, then double check the whole thing, or at least the first and last few characters.

What does this mean in practice though? If you need to be certain, make sure you copy the right address.

Bad actors can easily pregenerate adresses that mach those ahead of time.

Bad advice scammers/malware have huge tables of addresses they've generated that agree in the first N and last N characters. If a user is going to compare a subset they should make an effort to make it be an unpredictable subset.