It’s the same as us programmers driving cars or using kitchen gadgets. If something is out of the ordinary or the UX is difficult, we’ll think it’s fishy and lose a bit of confidence.
https://lawsofux.com/jakobs-law/
Jakob Nielson is a founding member of Nielson Norman Group that has studied UX for decades.
A site that is effectively a sovereign app has more freedom to defect from general interaction patterns, whereas one that is more of a transient app has less.