I don’t know if you’ve transferred any games from your Wii memory to an SD memory card. If you have, you’re already aware that it can take a long time. The data access speeds for the SD memory card are so slow that running a game directly from a card would be full of delays. For fast data transfer speeds, it’s necessary to have the game data reside in the system memory.

As players continue to download Virtual Console games, the Wii console’s internal memory will fill up. However, it’s important to note that the actual downloaded game and the license to have that downloaded game on your Wii console reside in two separate areas of your Wii Internal
Memory. The game resides in the Channels section while the license is kept in your Wii Shop Channel account.

What this means to you is that once you’ve beaten a Virtual Console game, feel free to delete it to make room for another game. If at any point you decide to play it again, access the Wii Shop Channel and download it again. It is possible to delete and re-download purchased Virtual
Console games as many times as you like for free, even if you were to re-format the console. This will allow you to free up the space you need for game saves and new Channels indefinitely.

The only way to delete or lose the license is to delete your Wii Shop Channel account entirely, which would then delete the licenses of all the games you’ve downloaded.