Yes, in order to download your “Game Keycard” games, you must get the game data from nintendo online services. This is why banning online services is considered effectively bricking the console, at least for all 3rd party games on keycards.

If an account is banned, another one can be made for free and the user can keep utilizing their online services… Nintendo obviously looks at that like a burden, and wants to financially punish that user, making them have to buy another switch. This in turn benefits them.