They work better in Linux than Windows, not to mention backwards compatibility.
EDIT: I may be wrong about newest printer models, 2020 and above.
EDIT2: Hardware problems are an entirely different issue.
CUPS is absolutely amazing compared to windows printer drivers which had whole ass critical CVEs several times already.
Even Apple uses CUPS
CUPS is horrible, and also had its share of critical vulnerabilities. It is just better than the LPD mess we had before.
It is not a Linux specific thing - it was developed when there still were a lot of UNIX variants around. Apple was a very early contributor, and had quite a bit of influence in making it successful.
It’s no surprise Apple uses CUPS. They wrote it, after all.
Edit: TIL Apple didn’t write CUPS themselves but they bought the company that did it pretty early in the game. Here’s a LWN article from the time, exposing some of the worries that came with the news of the acquisition: https://lwn.net/Articles/242020/