Cool? I mean sure, if when you're picking out a computer it's because you're going to run some variant of Linux/BSD on it then yeah, that's relevant. Or if you have specific Software needs that only run on Windows, macOS, or Linux then that's the decision made. But if you're just looking for a general purpose computer then they're absolutely competitors since the list of popular software that's macos/windows exclusive is small.
And if the argument is "well if you don't have high-performance needs and you're just <pejorative about what people use computers for> then why does it matter" the answer is because the battery life is incredible and the thing is unbelievably snappy and responsive.