While I appreciate the desire to show off your creation, a "Show NH" that requires people to sign up for a $20/month service isn't all that great from my perspective.
It expired months ago while my (paid) GPT account continues to function happily.
They don't use the phone for any kind of 2fa stuff. If they ever block my account, I'll just repeat the process.
On a positive side, I believe it's a matter of time. In a couple of months it'll be cheaper or free for all.