From the perspective of the developer there is no difference. They just configure kubernetes or docker to use a different Container runtime and keep using the same compose files, etc.

I think the point the OPs was making is that yes, as you say, developers can use containers without knowing these differences, but that there are actually real and important differences and maybe it would be better if more devs were aware of them.

Yes exactly.

I've had bugs when doing webdev stuff in docker that didn't crop up under one kernel that cropped up when using another. It's rare but it happens.