Note how often the refrigerant oil doesn't get out, only the gas. It's much harder to seal high pressure gases than low pressure viscous liquids.

Also much of the refrigerant in those consumer cans is R290 - aka purified propane. No ozone damage or global warming potential. People should actually be encouraged to use those cans instead of "real" refrigerants. I only recharge vehicles with R290 now as it's bound to escape again so it had might as well be a cheap and harmless gas.

I feel like all halogenated refrigerants should have been replaced by 290/600a at this point. Hydrocarbons are better in many ways and also dirt cheap.