I'd assume it isn't see through because you load it up with dirty dishes that sit for days before you run it. No one wants to spend days staring at the crusty spoon meemaw dipped in the peanut butter and licked like an ice cream cone before the wash is finally run
Modern dishwashers can easily clean tons of crust. That's why it takes them so long. As long as bigger chunks are gone and you clean the trap you are fine.
People who don't make a lot of dirty dishes? Running a dishwasher that is not full wastes water and energy. When I was single I would only run the dishwasher twice a week or so.