>Of course, the problem with this is you are just spending more money on filters, which is the expensive part.
For cost over time, twice the filters means twice the replacement interval, so the additional filter cost cancels out.
I'm sure it works but like any engineering decision it has pros and cons.
>you get to look at any collected dirt
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.
Flipping the fans isn’t great because then you have to clean the fans, this is why draw-through is the standard configuration. Also many designs like this rely on negative pressure to seal properly or even stay together. You might just have the lid take off like a helicopter.