Actually hydrogen can be a byproduct of different processes that produce industrial chemicals. For example if you want to make chlorine gas for treating water you start with a brine solution (NaCl + H2O) and then dissociate it with an electric current. The result is chlorine gas (Cl), sodium hydroxide (NaOH), and hydrogen gas (H). You have three useful chemicals that can be sold at profit with one process. Hydrogen is a plentiful gas that is far easier to obtain than a gas like helium.