You are ignoring the energy in the fuel. Which is arguably a reasonable thing to do as we don't have great fusion reactors yet and H Bombs are not exactly sold at Home Depot. But, it's still the kind of fuzzy thinking that leads you to assuming bad ideas will work.

As to 100W vs. > 100W. 100.001W might as well just be 100W in just about any meaningful way. However, Jet is vastly cheaper per watt of liberated fusion energy. https://en.wikipedia.org/wiki/Joint_European_Torus