It is sufficient for proof but not visible unless you direct people to it. A NIP-05 identifier is visible in your nostr profile (so people don't have to open up twitter) and leverages the trust you have built around your website. Using a paid service like nostrverified.com is pointless, IMO, because anyone can pay $5 to impersonate you. It's a bit harder to steal or hijack someone's web domain, though certainly not impossible.

You could also just do nothing and that's totally fine as well. Some people on the internet (rudely) demand authentication. But people make all sorts of demands that you are not obligated to satisfy.