Lu Zhiyu knew that atoms could exist as gases, liquids, or solids. Generally speaking, simple molecular control concerned only the movement of those atoms.
A much more difficult task would be the manipulation of the atom's internal rotations and vibrations, which could occur in various patterns. Those complex manipulations were still too hard to realize as of yet. Even mid-level mythical creatures did not have that capability since the rotation and vibration inside molecules occurred simultaneously in a linked and inseparable process.
Hmm, so suppose a user has complete control over all molecules. That would grant the user the ability to stop all molecules from moving. So, practically speaking, if the motion of an ordinary life-form was frozen, wouldn't that be the same as freezing it in time?