Pressure cookers are dangerous because water expands to 1700 times its volume as steam, and thus water acts like a big sponge of energy, and steam explosions can kill. A typical steam pressure cooker is run at 15 PSI or so.
A pressure freezer will operate with 9000 PSI or more, requiring a far more robust vessel. However, as water isn't compressible, a leak should be far less dangerous.
When comparing with isobaric(constant pressure) freezing the paper mentions that it consumes less energy because for food preservation you only need to freeze to -5 degrees, and most importantly there is no phase change process. Thus, you do not need to spend energy in that extremely energy hungry stage. They state a 70% thermodynamic efficiency improvement vs conventional isobaric freezing. That is quite a lot. If you consider that most of a house's latent energy consumption is used for the fridge/freezer I can see important impacts for energy efficiency, although the paper seems to target industrial freezing and not home freezing.
Really nice business cases for industrial uses. 70% energy efficiency increase would probably lead to tax rebates being available for potential customers, making them more likely to upgrade their systems. Improved food preservation would also be a good pitch to make to premium food producers, think fishing boats plus saves in fossil fuel. With expertise gained in my non-critical food preservation industry I would later pivot into the bio-sciences selling lab and transplant freezers.
Also the containers need to be eventually opened. Either this is extra step for processing, or, if that step is left to consumer, with all the complications of consumer friendly packaging requirements and recycling.