Question about Digital vs gamecart

I am wondering if any Switch owners could provide me with some detail on how digital games work on the system. specifically storage of game data. Ultimately I am trying to decide between Zelda on gamecart vs. digital download.

Question1: If you purchase Zelda for digital download, will the game data be installed on an SD card (if available) or does it need to reside on the system memory in all cases?

Question2: If digital Zelda CAN be stored on an SD card, is there are a major hit to performance (when compared to gamecard or system memory)?

Going all digital seems to make more sense for me if the bulk of the game data (data that's stored on the gamecards) can be stored on the SD card and there isn't much of a hit to performance.

Thanks.

It seems like if you have an SD card plugged in, the game will install to it by default. With a decent SD card, the performance hit (basically just load times) is minimal.

I'd imagine it would depend on the quality of the SD card. I hear Samsung EVO ones are great

If you have an SD card installed (which you should if you are considering digital games) then the digital game will install to that SD card. The only data that will remain on the internal system memory will be your game saves. I haven't seen any benchmarks to compare performance of game card vs. SD card vs. system memory, but I expect any differences would be negligible.

Can you afford to pay £60 a pop for top titles?

I saw a brief article someplace showing that the physical carts have slower memory than some of the high end memory cards; leading to a slightly worse experience if you buy the games physically rather than digitally.