Why Can’t i put Wampa by himself on defense?

Fromsucktoblow

Id like to be able to put wampa by himself on defense for GAC so that his omi can be used to the best of its ability

KvotheQGBQG2

If you put an Omi Wampa on defense it would get erased very easily. You are much better off choosing who to use that against, than having your opponent have the ability to choose what to use against it.