A lot of stuff becomes feasible with free unlimited energy. For instance, carbon air capture (could even become a protein source) and green hydrogen (for applications like production of iron via direct reduction, so we can finally get rid of blast furnaces).
Why do you think fusion would provide free unlimited energy? With any design even slightly visible on the horizon right now, a single plant will cost billions of dollars and barely produce a few MW of energy. This is much worse than any equivalent investment in solar power, which similarly requires 0 fuel.
