it's fake interest though, just build and release early. Not saying spend months, but beta signups to a non-existent product is false signaling. People do this because they have nothing to give up. It's like VCs not saying no because, who knows, maybe they will pull it off soon and I'll take a look again then.

Get whatever it is in the hands of people, better to talk to strangers in person than to do a beta email list before starting building.