The more important number is "about one hundred times greater than required to support a 100% global renewable electricity system" which does sound pretty good.

Are these locations close to the areas where the energy is needed? Australia is big, and transmission lines, not cheap.

(By the same token, Sahara might be an ideal place to locate large solar power installations to feed the entire Eurasia, were it not for the transmission.)

They're cheap enough. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8661478/ Going by this you can get 200 miles of long distance line for each penny per kWh.

And look at the map, they seem quite widespread.