

Ideally there are no harmful combustion byproducts when used in ICE, the reality is probably less harmful combustion byproducts, not none
Hydrogen is lossy,
Conversions being inefficient,
Molecules small enough to migrate from containment,
Embrittlement of pipes & tanks
3 or more times the infrastructure per watt delivered, a huge investment in resources
I suppose if there is excess generating capacity, hydrogen could be used as a storage medium for night time
Founders Intent was 1 congressperson per 30,000 people to comprise a district, not 700,000
It would be much harder to gerrymander smaller districts effectively :D