For every purchase made, it feeds his delusions that he is a legitimate artist and this is a legitimate form of employment. He thinks this is an alternative to a normal job. If people buy, he's going to keep doing this (as he should). As long as there are tards like watermellon to throw their money away, why not cash in? But don't pretend you're helping his situation as if you're the "well-intentioned troll". For every sale made, it just extends the duration he will continue selling and therefore not improving his situation in life. We all know this will never happen, but buying guarantees it.
I think your last sentence is correct. For a decade Chris lived off the tugboat, showing no inclination to work. The tugboat is adequate to fund a lifestyle that works for him. Sure he would like a little bit more money, but who wouldn't.
He has indicated a few times, usually under pressure from Bob or some theoretical ex, that he might get a job at some point. But he never really tried. He didn't want a job, he wanted an excuse not to have a job. A couple failed job applications worked perfectly for him. He could say "Look, I applied for jobs but they didn't want to hire me because trolls/autism. Now you have to get off my back".
The tugboat reinforces that for him. Not only does it fund him so he doesn't need to work, but it is given to him with the message "You aren't really capable of working, so you don't have to. Here is some money to compensate for that". It is easy to internalize that message, particularly since it is one he is happy to receive.
So it's hard to say that "funding" him has any negative effect. If you are really anti-Chris and honestly feel that Chris having more money is a bad thing for the world because of his personal flaws, then I suppose I see it. But it doesn't discourage him from getting a job, because getting a job wasn't something on his radar anyway.
Chris does definitely have delusions about Sonichu and his artistic skills. But I am not sure it is fair to call him delusional for thinking this is a legitimate form of work. He provides something people want, people give him money in exchange for that. There is an inherant "legitimacy" to that. Of course there are other layers to it, but I don't think we can ignore that bottom line.