They wanted the anime to match the video game's world
The key is that some complexity is hidden, because it requires certain knowledge to even be aware of it
[When Attacking] By trashing up to 3 level 6 or higher cards in this Digimon's digivolution cards, among your opponent's Digimon and Tamers, delete 1 with the lowest play cost for each card trashed
Honestly I think for something that can modify multiple opponent effects in one go, making them fizzle as they turn into Foolish Burials, generic GY retrieve effects, and extra draws, that's strong enough to warrant the ability to respond to it
Once Sidar is in play, you can bring back those discarded Knights to the battlefield one by one when he deals combat damage to a player
In both cases this leads to Yugi making mistakes during the Duel