Reply from a Nintendo rep in an email.
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.
Source
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.
Source