No, this doesn't make sense. If your goal is to reduce fossil fuel usage, and Bitcoin also incentivizes fossil fuels, then there's no reason to expect that Bitcoin will help reduce the share of energy produced by fossil fuels. Worse yet, if it increases total energy consumption, and doesn't affect the percentage produced by fossil fuels, then that will increase the absolute amount of greenhouse gas emissions.

Your arguments work just as well for reducing risk for investing in "marginal" fossil fuel sources.