Why is the Memory Card used an element tracked in Animal Crossing speedruns?

Was browsing some speedruns on Speedruns.com and saw something weird. https://www.speedrun.com/ac#All_Debts

In Animal Crossing speedruns, the Memory Card size is tracked; just like other things like language played.

Do the Memory Card used change anything in Animal Crossing Speedruns? Or is that information tracked for seemingly no reason?

Solution 1:

According to the attached speedrun.com forums, the size of the card may impact save and load times. It is unclear how much of an impact there is, but the consensus seems to be that a 1019 block memory card has the fastest save and load times. The top 3 All Debts runs all use a 1019 block card.

It's also worth noting that third party memory cards are banned, which is why size is tracked, since official Nintendo memory cards of the same size should have the same performance.