I actually really like it as an aesthetic choice. It's possible that the roll itself might slow the pace of gameplay, but in principle seeing the dice roll on screen is a fun way to get players to connect with the game. I think it's a way of allowing a different kind of immersion, giving players the ability to feel the tension of waiting to see if the dice are in your favour. And to relate that to the primary topic, I think they should definitely show both rolls when you have dis/advantage.
It’s a nice touch. However some players prefer the numbers to be happening in the background, and that there is about as foreground as you can get.
I recon I’ll start off thinking it’s really cool, but it could get old after 20 or 50 checks. Should definitely be an option to hide it. As well as hiding passive checks as a separate option.