Because a fuel cell is type of electrochemical device. It is literally a type of battery. So whether you are using a li-ion battery or a fuel cell, you are turning chemical energy into electrical energy. Also, the process of distributing hydrogen is comparable to the grid and has similar losses. The latter of which will see a dramatic reduction in efficiency as more renewable energy go onto the grid. Specifically due to the need for energy storage.

There are no experts saying hydrogen for cars is stupid. You are just hearing a lot of pro-BEV marketing and their fanboys. Of course, some of them pretend to be experts, but they are not.

In the long run, BEVs are going to die off because they are not economical vehicles. They cost far more than conventional cars and require huge amounts of new minerals for the raw materials used to make them. If the goal is just to have an EV, then the answer is a type of EV that does not so much raw material nor cost so much. That leads to ideas like PHEVs or FCEVs.