Source: Rebecca Spear / iMore
Best answer: Yep. If you own the physical or digital copy of a Nintendo Switch game, the game save data for the Switch is in the system's memory. So, if you're on the physical version and want to switch to digital instead, you should be able to do that without a hitch.
Your data is stored on the console
Unlike other Nintendo systems, your game save data for the Switch is stored on the console's system memory, not on the cartridge. Even if you buy the digital version and later archive or delete the game from your console, your game saves will be preserved.
The save data is also generally associated with the individual account, so as long as you're signing in as the same user, you should have access to the save data. In other words, if a user account is deleted, all the save data is deleted too — and can't be recovered.
Perks of physical games
Source: Rebecca Spear / iMore
If you're into building a credible bookshelf of video games, then you'll definitely want to buy the physical cartridges. You also get all these great benefits of physical games. For example, you don't have to wait for it to download before playing, and you can borrow and lend games with friends and siblings. Then, when you're ready for your next awesome Nintendo Switch game, you can sell or trade-in games you're not playing anymore.
Plus, your microSD card can be smaller since it's holding only game save data instead of the entire game — that could save a bit of money. Still, it may even out in the end since you'll probably want the best Nintendo Switch game case we could find for your budding game collection.
Perks of digital games
If you're trying to save space in your home, consider buying the digital version instead. Digital games might be for you if you don't want to worry about games getting lost or destroyed, or having cartridge cases or other physical storage.
If you're worried about the environment and plastic waste, digital games don't generate any of that. If digital calls to you, we recommend a high-capacity microSD card like the Samsung EVO Plus 256GB.
Either way, you're good to go
Whether you decide to buy the physical or digital game or start with one and decide to move to the other, you should be able to continue with your game save data from either version of the game. If you really want to be sure, you can enable the Save Data Cloud option on your Switch and check for the game in the backup list.
Go digital

Nintendo eShop Gift Card
Buy the games you want and play (almost) immediately with a gift card from the Nintendo eShop.
If you don't have space or just like not switching out cartridges, digital games are the way to go. Gift cards are always a great option to give for special occasions or even just because!
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