I have watched the Video on this product, Probably not too bad to use in a pinch, They did try to make it Safe. However they do not Address if the refrigerant could contain any Flammable substance mixed in,Like Propane.
Or that there is still a Some amount of Moisture in the sytem that could hamper performance,and deteriorate Parts. Moisture in an AC system Corrodes from the inside.
Even though that would be more of a concern in vehicles with more substantial leaks. Though they require safety glasses they do not warn you to shut the AC down before disconnecting the can from the fill port. Which could be Key when sometimes those port valves hang open Ocassionally.
If you Decide to seek Professional Help for your AC woes in the future. Let your Mechanic know that you have used this type of product, The sealers used in these types of products used can damage, Professional AC equipment when the get serviced, a warning would be the Fair thing to do.