I think the hype comes mostly from credulous futurists who love the sci-fi aesthetic, not from people who actually think critically about the potential of the technology. It takes a serious suspension of critical thinking to believe roads made out of solar panels isn't a really dumb idea.
Solar roadways only value add is "we found more space to put panels" and that's not a serious problem as there's plenty of space for that.
Roads are already costly and this would just make it worse.