Even in naval warfare minefields are only really practical when deployed in narrow and limited-"path" pockets of water. Bays, straits, etc.

Which is still a bit unpractical to pull off in open space because of how things scale vs ship size vs density requirements for sensible coverage. Plus three-dimensions of movement of course.

The few exceptions might be if you're deploying minefields near or around a stationary strategic location like a station or a small moon, but even that's going to be more costly than it's worth a lot of the time.