You need to learn how hydrogen is produced. It only emits water at the point of use but most at present is made from a base stock of natural gas - not green at all!

It is also worth noting that every time you convert raw energy (oil, gas, sunlight, wind, tidal etc) into something useful you get conversion losses - eg: converting petrol in the tank to motion creates frictional and heat losses, converting gas to hydrogen creates losses and further losses when hydrogen is converted to electricity.

As things stand the only worthwhile uses for fuel cells are very specialised - in mines, to provide a power source for very remote sites, etc. They are a technically interesting blind alley - the only question you need ask is whether making hydrogen economically is more or less likely than improvements to battery technologies.

There are two big snags to hydrogen: it has to be stored under fairly high pressure (unless kept extremely cold); which increases the danger of a severe explosion. The same applies on a vehicle as well as a filling station. Zero exhaust pollution is a nice tempting idea but there is a big downside.

There are downsides to everything if you look hard enough, electricity in itself is a killer so what's the difference, we have to go with what's developed which could be both Hydrogen and EVs.

which as yet no one knows and my guess is it will be both, Hydrogen possibly may get the sales for its mileage compared to EVs assuming its development is as fast as all electric

It is and will be interesting to see what happens over the coming years