Hydrogen vs. Battery Electric Cars

Besides the efficiency issue:
1. The majority of planned Hydrogen production planned is not from water electrolysis. It's using a steam-methane electrolysis. How effective is this for reducing CO2 emissions?
2. The Hydrogen Fuel cell uses membranes of Platinum. It's rare and expensive. How will they get around this without losing more efficiency and causing a higher  degradation rate of the fuel cells? what does the degradation rate look like vs battery? I guess my main question is "is this technology really sustainable?" 

Please don't give me a Hydrogen tech salesman answer.

Yes, you may have just put the info out there for the curious, but you didn't ask any critical questions.... something that's a cornerstone of Physics. 

It seems like you've just become a megaphone for a certain pocket of interest.