Restating the point without additional explanation an argument does not make.

In what world is it reasonable to implement unrequired, unnecessary, and costly, features and call that a net positive in all cases under all circumstances.

You're comparing entire solutions. That's not what they were talking about. They were talking about individual features.

Also, some sources are more flexible by their very nature and get the flexibility for free.

But more generally, lacking flexibility is a negative by itself. It's an acceptable negative if adding flexibility would cost more than the benefit, but it's still a negative.

"But more generally, lacking flexibility is a negative by itself."

Not for baseload generation.

It's still part of the same grid as non-baseload generation, so the lack of flexibility makes the entire grid less flexible. So yes it's a negative.

And most people would call "can't be used for the more difficult parts of power generation" a negative too.