The Difference Between Archiving And Deleting Games On Nintendo Switch
If you've ever found yourself needing to free up space on your Switch, chances are you've seen it: The choice between deleting a game or "archiving" it. When you need more storage and you need it right now, you may not have much time to think about your decision. Thankfully, the most important thing (i.e. holding onto your save data) is consistent between both options, so no matter which one you choose, you don't have to worry about starting over from the very beginning if you ever return to a game you've removed from your system.
Regardless, if you're running out of space on your internal memory and/or microSD card, and decide you need to clear some things out; you can wait for your Switch to prompt you, individually highlight a game's Options and select "Manage Software" settings from the home screen, or go through Data Management in the System Settings.
With the choice between both options, ultimately, it all comes down to how likely you think you might be to want to go back later on and play the games you delete.
Nintendo Switch: Archiving vs. deleting
Functionally, archiving and deleting are almost identical processes (via Nintendo). As previously mentioned, your save data will be safe no matter which one you choose. The same applies to any videos or screenshots you've saved from that particular game — all of that stuff will stay on your Switch until you manually remove it yourself, either from the Album or from the Delete Save Data menu.
Both choices will simply delete the game software itself from your Switch to free up storage space. That being said, archiving makes it just a little bit easier to go back to a game you've removed should you decide to reinstall and play again.
When a game is deleted, all evidence of it is gone from your Switch (aside from saved data and saved screenshots or videos). If you want to download it again you'll have to choose the "Redownload Software" option at the bottom of the All Software menu, or dive into your Account Information page on the eShop.
But if you archive a game instead, its icon will remain on your Switch even after the game is removed. Selecting that icon will prompt you to download the game again, at which point you may need to shuffle a few more things around to make space for it. If you decide you'd rather not have the game's icon cluttering up your home screen or All Software library, you can still go in and select Delete Software to get rid of the icon (while still keeping save data, etc.) as well.