So Zorbfloater became a tanker (and lifting units) without any capability of killing.
Why bother with them at all then? Lifting units is a cool feature but it is difficult to utilize (and you can accidentally drop a unit on your own infantry), and is not as dangerous as decimating infantry blobs with ease. You try to kill tankers because they pose a threat, not because they have a lot of HP, and ability to lift vehicles is not that much of a threat.
Lifting a unit effectively takes it out of combat, if only temporarily. With enough floaters and some micro, you can disable the bulk of an enemy tank force. There's a reason this feature was removed from the Magnetron (this, and that it's even more OP with mind control). Occasionally dropping the enemy vehicle in water or on top of another enemy is just the top of the iceberg.