The same applies if the beaming is done with an optical laser instead of a microwave.

Optical laser is rather inefficient at converting electricity into optical energy. Surely there are some low-powered diodes where one can get over 50%, but for powerful lasers efficiency like 1% is a good number. Consumer microwave ovens on the other hand has efficiency like 65%.

Sure, that's true - I guess microwaves still could have some benefits, for attenuation in the atmosphere/weather maybe ?