Anything involving hydrogen is really wasteful. This probably even moreso. Plus, fuel cells cost hundreds of thousands of dollars for one big enough to run a car.
Not so, really. It makes an excellent motor fuel, with three and a half times the explosive capacity than gasoline, which is a hydro-carbon, after all... really a method for delivering Hydrogen stored in a carbon bond for storage at ambient temperature. In 1980, my friends and I were experimenting with metal hydrides, like Nickle, and came to the conclusion that it made an excellent way to store energy using non-peak grid resources.
The greenies love it for the same reasons I liked the clean air aspect, in a way, back before it became a fashion statement. It's exhaust is steam, which is ironic. The Global Warming minority is so worried about Carbon Dioxide as a Greenhouse Gas when water vapor is, by far, the most influential of the greenhouse "gases."
Makes a lot more sense than the ice-slinging, bird-killing windmills city folks want to deploy anywhere in rural areas where people like their peace and quiet.