Generally, the economics of nuclear involve a very large upfront cost followed by cheap energy afterwards. Maintaining existing plants usually makes sense but building new ones should only be done with careful consideration of other options in the long term. On demand power can be used to supplement a grid so having a variety of options makes sense.

But it seems like everybody just picks up one thing as their pet solution and tries to promote it in absolute terms, which doesn't really make sense. Different environmental conditions call for different solutions, and imperfect options can still have a use case. There isn't really a "best."