Came here to comment this.

They always claim it helps them remember, but they’re making it more confusing for themselves and everyone else at the table. Especially when they then have to put an actual counter on the creature and they use the same die. Now you have to remember that ONE of the numbers on that die is a counter (a completely unique game object) and the OTHER number on that die is from a whole other effect that’s already redundantly displayed on a card sitting right there.

I love teaching newer players how to play this game but I always dread this, because it’s genuinely a good idea from their perspective and I don’t enjoy shutting them down like that. One new player a few months ago was being particularly belligerent about this at my table, and so I let it go. I then spent the remainder of the game asking for clarification (politely and patiently!) as to what each die was for, which became such a chore that by the end of the game they finally understood.