We all know restriction enzymes are proteins, but we never freeze them. They are instead provided in high glycerol containing solutions by companies and stored at -20C. Is there a reason why this is so?
It's just so much more convenient to have the enzymes ready without having to thaw them. The main reason you freeze enzymes is to keep them active, if you figure out a buffer that keeps them unfrozen without compromising activity, that is a huge increase in convenience.
Not having to thaw the enzymes before use saves a lot of time, if you can manage to keep the enzymes active in those non-freezing conditions that is a clear advantage.
Glycerol also stabilizes proteins in solution, and multiple freeze and thaw cycles can negatively affect enzyme activity for some enzymes.
Freeze-thaw cycles denature proteins through local pH change effects