Hydrogen isn't "better for the environment". You're assuming we get hydrogen for free. At the moment, most hydrogen is created through steam reforming of methane, thus methane, right now, is greener than hydrogen just because you save the energy cost of the reforming process.

Hydrogen is harder to store, has a lower energy density by volume, and is massively more dangerous than methane thanks to its enormous flammibility limits and its high flame front speed leading to larger explosion overpressures. Hydrogen has more energy by mass, but mass is not that relevant thanks to its enormous volume requirements forcing structural masses to be larger (just look at the size of hydrogen rockets versus falcon 9).

You could argue that hydrogen can be made via water electrolysis and renewable energy in the future, but this is also true for methane being made from water and carbon dioxide. What is also interesting is that SpaceX is betting its entire Mars architecture on getting the 2xH2O+CO2->CH4+2xO2 chemistry working via the Sabatier process. It is also a step in carbon capture and reutilisation, a key technology if we're to reduce CO2 emissions.

Overall, hydrogen is not the solution to the energy crisis or the solution to rocketry. The solution to the energy crisis is decarbonisation of energy production (no need for hydrogen at all there, just use batteries, solar, and wind). The solution for rocketry around the solar system seems to be methane, with the only possible exception being the moon which has no carbon source.