HotelTonight's model is to find and offer up rooms for last-minute demand that would otherwise go empty. Hotels are happy to offer discounts for these. It's really just automating the same deals you could get if you called.
The bigger brands don't offer any discounts compared to their official sites. They can change prices many times during the day, but the official brand's website will always be the cheapest.
Edit: I'm going to have to retract my comments about cheapest price being on official hotel brand websites. I did a cursory search and find many cheaper options on Hotel Tonight (and expedia) for same day reservations than the brands, and while I haven't looked at all the brand's best price guarantees, at least IHG's exempts them from having to provide the lowest price within 24 hours of checkin, so it seems like a loophole to let them dump rooms for cheaper on third party websites day of arrival.
No, it wasn't there original thing. Last minute hotel deals have been a thing for decades online. Oh, they have an app? That doesn't make their ideal original, nor were they the first to book 'last minute deals' on an app anyway.
Last-minute same-night deals was HotelTonight's entire business before they added all the other features like memberships and future bookings. That's where the name comes from.
I didn't mean they were the first to do deals but nobody cares about that anyway. Users only care if it works for them, and HT has one of the smoothest apps with some of the biggest discounts. When I started using HT years ago, I could book a room in less than a minute at a lower price than any other online source.
Anyways, as to the original point, they might have lost money on some deals but not all of them, and this is directly from private hotel owners I spoke with.