I think people like it because the control flow of a given program is more obvious when you write it that way. No one can "throw Foo" three libraries down from their caller as an "API". See https://go.dev/blog/errors-are-values
I think it is a few things together. The rootless and daemonless design leads to UX differences with Docker. Because of the differences, it isn't just a drop in replacement; porting applications can be a pain if they do anything weird (no network isolation, --containall isn't default and still is a bit different when on, etc). And Docker has a ton of momentum and usage.