Fuel is not a major cost right now, but it inevitably will be at some point. Current estimates are that we have 80-250 years of uranium left [0], so we could use a different energy source for the long run.

The difference in radioactive danger, is because not all nuclear reactions are treated equally. Tritium decays once, emitting a 0.019MeV beta particle [1]. Uranium creates an avalanche of particles [2] for a total of 51.7 MeV. So it has the leeway to be both more radioactive and to be it for longer. But both the type and energy of the radiation have intricate effects on how they interact with biology and so how dangerous they really are.

That said, exactly how radioactive fusion waste will be is a bit a philosophical problem, as nobody knows what the minimal requirements are for a functional plant.

[0] https://bettermeetsreality.com/how-much-uranium-is-left-in-t... [1] en.m.wikipedia.org/wiki/Tritium [2] https://en.m.wikipedia.org/wiki/Decay_chain