While that may be a decent litmus, its nowhere near foolproof and may filter out the very people who might otherwise have the most passion and staying power on nostr.
For example several members of my meetup group jumped on nostr today. They showed up with profile pics and lnaddresses cause I had been talking their ears off abt nostr for the past year. They simply came prepared and are very passionate. Immediately assuming they're illigitimate cause they came prepared to jump into the community seems backwards to me.