>you get to look at any collected dirt

If that's your biggest worry in life, seems like a high-class problem! Many people are satisfied 'just' protecting their heart and lung health.

However, if you really don't want to look at it, you can always flip most DIY designs inside-out so the fans blow in and dust collects on the inside instead of the outside! This doesn't clean the room quite as efficiently, but if the appearance of dust is a major concern that should be a fix.