Yep efficiency isn't great - but as I said, better then the efficiency of throwing excess away ( zero ).
There is also value in the ability to store the energy - not as efficient as something like using water to store potential energy ( ~75% ), but there is value there.
I'm not somebody who thinks it will be hydrogen everywhere - frankly electricity is easier to distribute and we already have a good infrastructure - but that's not to say it doesn't have a role.