No this is still the level below needing a SCIF. The USG really tightened this stuff up in the 2010s and highly restricts what you can do with CUI. That's why there's a whole parallel FedRamp-compliant cloud ecosystem.

But in terms of how common it is, pretty much everybody in Fairfax County works in a company with rules like this; it's a big part of why the tech culture is so different than Austin or SFO.