GaN-FET is not necessarily a MOS-FET strictly speaking. > By choosing GaN, the MOSFET can be switched quicker without wasting too much energy as heat. That in

GaN-FET is not necessarily a MOS-FET strictly speaking. > By choosing GaN, the MOSFET can be switched quicker without wasting too much energy as heat. That in turn means all other components (capacitors, inductors) can be made smaller in the same ratio. Faster switching frequency of the whole circuit is not necessarily an attribute of the material. There are silicon ICs with high switching frequencies for things like powering CPUs, and GPUs. They are of course physically bigger, and a bit less efficient. What GaN switches put on the table is having a single transistor being able to do this, and thus allowing much simpler circuits, basically a drop in replacement for existing silicon devices.