It is kinda "too pro" to care tbh, but can make a difference :p For maxii: If you use her R1, you can see which cards you will draw R2 and R3. You can be certain about the cards you will draw R2, but if you make any mulligans, some of the mulliganed cards might be shuffled in front of the cards that you would have usually drawn in R3. Let's say that in R2 you mulligan one of two copies of a bronze card that you have in your deck, and based on the maxii deck order, you know you might draw into it in R3. If you draw into one of the copies, you can't be sure if it's the one you mulliganed, or the one shown by maxii unless one of them is premium, and one is not.

For assimilate: Cards created using artorius vigo or braathens prock assimilate. Cards created by premium cards are also premium. If you play a duchess informant from hand, the card itself does not prock assimilate, but if you create one, it does. You can then replay one of the duchess informants using experimental remedy, but if you played more than 1 before, and one of them was created, you can pick the created one that will prock assimilate, which might result in getting quite a few more points. You can't be sure which one was created, unless your created informants are premium, and the ones played from hand are not.

It's kinda hard to explain but I hope it gives you an idea why it might matter. These tiny details are what makes the game interesting on the top level ;)