No, this is not just a phase. Today, over 80% of new vehicles sold in the United States contain an A2L refrigerant. Just like the AC industry, the automotive industry worked to ensure that safety issues were addressed and to make the transition seamless to end-users.
They are used in window, room and automotive air conditioners, as well as in mini splits, variable refrigerant flow, chillers, hot water heaters and other products around the world. In 2018, 26 million A2L HVAC-R units were sold throughout the world in homes and businesses. Refrigerant molecules with reduced numbers of fluorine atoms generally have lower GWP, however, that leaves more hydrogen atoms, which increases flammability.