On HN, and especially regarding "infrastructure" services that you might depend on indefinitely for something, "what's the business model" isn't a question about how the service will be enshittified. Rather, it's a question of what incentive there is to keep a free service like this running. If there isn't one, then nobody should use the service, because it'll very likely get shut down as soon as it gets popular enough for its hosting costs to become nontrivial.
What's your alternative? Nobody wants a corporate solution, but they do want free services that fly under the radar. Of course not all of them last forever, but what better choice is there?
It is crazy for someone to expect someone to use a service that has a 99% chance of getting shut down in a year when the domain name needs to be renewed. If there's no plan, there's no reason to use this for anything, ever.
I hear what you're virtue signaling, but people DO have a right to wonder what will happen if a link redirect service runs out of money and kills their links