If you're building a new type of anything, a concrete description of what's special with screenshots will go a long way. I'm not about to sign up for anything without any idea of what it's like and what's different about it.
If you’re going to dismiss good actionable feedback, why bother with a Show HN? These rarely get many comments and the only two you have can me summed up as “I would consider trying it, but you’ve placed an unnecessary barrier I don’t want to cross without knowing what’s on the other side”. That is reasonable.
> I’m personally tired of hearing this
Because it is a mistake as serious as it is common. As another commenter[1] observed, it’s a fault large enough to make your service die unloved and untried.
What I mean is that adding screenshots and such is not going to make a difference for the target audience.
Or to put it another way, here we are on Hacker News and not a damn bit of that advice would be good for us.