[bramgg]

It is already. From the Show HN Guidelines[0]:

> Show HN is for something you've made that other people can play with. HN users can try it out, give you feedback, and ask questions in the thread.

> A Show HN needn't be complicated or look slick. HN users are comfortable with work that's at an early stage.

> If your work isn't ready for people to try out yet, please don't put "Show HN" in the title. Once it's ready, come back and share it then.

> For example, blog posts, email signups, and fundraisers can't be tried out, so they don't count as Show HNs.

[0]: https://news.ycombinator.com/showhn.html

[taco_emoji]

It doesn't sound like that's proscribing user registration (account creation), more just stuff like e-mail newsletters.