Could have just the opposite effect you are looking for! Be careful what you ask for from the Feds!!
Actually it might have a negative impact or unintended consequences - as it would require a face to face visit with a doctor to write a prescription. Technically it could shutdown recreational marijuana sales in Colorado etc.
Federal Preemption is a legal doctrine that where the US Government regulates a particular field, State and local laws are overridden and of no effect.