> Because large scale production is generally more scalable and efficient

Rooftop solar is an example of small scale decentralized energy production, maximum efficiency is not the only relevant metric.

> And you probably don't want dozens of "microreactors" scattered across cities

Why not? If they're considered safe and pass all inspections, what's the problem?

A nuclear reactor is generally treated as a high security facility. I don't know how this new reactor works but I thought it was safe to assume something like a terrorist attack on one might be bad. It's also a lot more work to inspect and control them when scattered.

Rooftop solar does not have these issues.