Why is it that most MiniDV cassettes have only the left-side tape visible?

The left side usually has a see-through window but the right side is usually covered up with the casing. Why were MiniDV cassettes designed this way? It obscures some valuable information like how much the tape has been played through and if there are any problems with the way the tape is wrapped around the right side.

VHS tapes for example always had both sides visible. Same with 8mm tapes. Why is it a lot of MiniDV don't?