I drove 1800 miles in a Hydrogen Car

AS a child in the 60,s i used to play with hydrogen using milk bottles a large lead acid battery, i would put the milk bottles upside down over the cells of the battery and charge capturing the gas (hydrogen/oxygenmix).
Then i would line up the bottles and put a lighted max across the bottle tops.
A fast blue exploding flame would result, then i would separate the gasses oxygen and hydrogen by using + and - terminals in the cell.
i was 8 yrs old at this time it seems that mankind has not moved on much more since!.
why fuel cells? why not burn the gas with the oxygen this would provide more energy, use spare capacity wind/wave/solar power to produce the said gas?.