I know it's all about A/B testing and iterating and minimum viable product, but a sexy signup form that clearly required no time investment of your own does not make me think you're going to build a good product. It says "I'm a 'serial entrepreneur' cranking out crap to hope for a big pay day. If my product sucks and I get bored, I don't care."
It makes good business sense for the most part, but on a personal level I don't much care for it. It's the user's choice to opt in, and if the product genuinely seems useful there is a chance for mutual benefit. If not, just don't sign up.
On a separate note, what's to stop me from making up a bullshit project, putting up a fancy web 3.1 Hot New Product launch page, and just selling your emails to spammer lists? I can just put an empty and "personable" promise on my signup page and lie. "We won't spam you. Promise."
The whole thing makes me jaded about web entrepreneurship. I've been grinding it out on one company for 30+ months, so when some 'serial entrepreneur' just craps out mediocre work and gets paid to do it, a piece of me dies on the inside. Maybe I'm just old-fashioned.