It has proven to have minimal effect on transmission and an unreasonably short half life. 

The root issue I see is how the manufacturers are using a single [effectively cloned] protein rather than a disabled cultured virus. 

Because they’re using only a protein the body is likely to primarily attack that part that’s mostly responsible for secondary symptoms rather than the nucleus that’s actually responsible for replication and infection. 
That ironically makes exposure far less safe for people with compromised immune systems as those with clear symptoms are more likely either to be avoided or to identify it early and stay home compared to arrogant Typhoid Mary style mild or passive carriers. 

Normally when vaccines use cultures there’s room for individual mutations allowing your body to develop a broad set of resistances to the virus rather than the single version selected for making mutations and warning resistance all but guaranteed. 

The benefits of the current round is primarily on the infrastructure side. Once a supply chain has been developed it can be easily modified on short notice with new genetic information rather than having to develop a new chemical solution and wait for the material to be developed. 

It is a valuable technology to have available especially as a stopgap option for real emergencies and for the elderly who can’t wait, but for the vast majority it doesn’t really make sense, and the regulations are about as logical as The satanic panic with a mountain of perverse incentives.