If a company didn't have a sustainable business model yet and was losing money, then yeah, it wouldn't make sense to pledge for Long-term support. It's kind of a stamp of "Yup, we've our cashflow under control, happy to keep doing what we're doing".

Alternatively, the pledges can all be used individually, so you could use some of the others without a commitment to long-term support. That's a stamp of "We're not exactly sure how sustainable this idea is yet, but we have ethical standards so we'd prefer to let the company fold than to screw you over (privacy/selling data/quietly raising subscription fees etc) to try and reach profitability".

In both those cases, it would make me feel more confident as a user signing up (especially if they're an app for managing some private/personal part of my life).

Yeah, it makes an exit more difficult. Of course if you make no promises to your users, you can make more money because you're free to sell to the highest bidder, no matter what their intentions. But that's kind of the point of these pledges - as a founder it's saying "I care more about maintaining certain values for my users than making myself rich through the first acquisition offer than comes my way". I'm sure there are founders that think that way, even if they're in the minority - that's really who I'm trying to reach.

EDIT: Also, what I've got in the draft is a clause for each pledge about the correct procedure for retracting the commitment (properly informing users and giving them time to act), so if an acquirer really wanted to go back on the pledges they could - but, rightfully so, they may lose some customers who felt strongly about those values.