It could quite literally save the world in terms of clean energy. I can understand why one would at least try.
As with fission, most of the operating costs would have nothing to do with buying fuel. Solar and wind power suffer none of these costs, so fusion, like fission, would be wholly unable to produce power at a price anyone would pay without being forced to.
The fission plants still operating will find themselves increasingly unable to produce power at a price anyone will pay, so will be mothballed long short of their design life.
And, who do you imagine you are fooling?
Regarding Diablo Canyon nuclear plant: “The plant produces electricity for about 6 cents per kWh, less than the average cost of 10.1 cents per kWh that PG&E paid for electricity from other suppliers in 2014.” https://en.m.wikipedia.org/wiki/Diablo_Canyon_Power_Plant#:~....