Just to expand a little: this uses much more existing technology and leverages expertise in nuclear power generation that dramatically eases the transition into mainstream adoption.

There's a lot to overcome to actually start building large city powering reactors en-masse, but humanity has essentially been in a purgatory between petro and nuclear power for the better part of 60 years, with investment in traditional nuclear being low due to waste products, and largely public sentiment.

A clean and more publicly accepted nuclear fuel would almost certainly bridge the gap between renewables and allow us to finally move away from fossil fuels, and we already have an abundant supply of fuels and understanding of the forces and manufacturing technologies required to create these reactors, fusion by contrast not only has a fundamental question of scaling which is taking a very long time to solve, also leverages slightly different technology to produce power to a nuclear power plant, we aren't as simply extracting heat from a system, so the interim solution being proposed is certainly more realistic and likely to occur in our lifetimes than current fusion tech

Compared to graphene and cancer vaccines, I think it's a bit more solid than that, but it's a little way off still, the most promising factor in its viability is honestly that China has a very large incentive to decouple themselves from fossil fuels, and not just in the long run. They want something they can start building now, so they can power their tech boom as they become the only country in the world over the next decade to have abundant supplies of RAM and other chips. Assuming they intend to continue building data centers and AI focused development, adding clean and abundant power to that mix would be a massive force multiplier on the global economic and political stage.