However, I feel that CIWS is mostly defensive security theatre. How often are do they actually work in the real world? The number of attacks on vessels carrying CIWS are so small. As a result, CIWS hardly get any real world practice. Events would be studied by military and manuf., then software updates made. As a counterpoint: Think how many cruise missiles have been fired in the last 50 years -- lots(!). There are plenty of case studies for military and manuf. to improve software. (I assume this is also how anti-missile systems are improved, like the US Patriot system.)
FYI about this ship (Moskva):
https://en.wikipedia.org/wiki/Russian_cruiser_Moskva
Says CIWS system is: AK-360
https://en.wikipedia.org/wiki/AK-630
See section "Service history" for some *highly* speculative writing!