You can easily look up yield by residency for any UC campus at:
https://www.universityofcalifornia.edu/infocenter/freshman-admissions-summary
The Fall 2018 numbers aren’t available yet. For Fall 2017, the UCSB yields were:
20% CA residents
7% US out-of-state
12% International
And yes, the US out-of-state yields were much higher at UCB (30%) and UCLA (21%).
True – although with an estimated cost of attendance >$60,000 and no financial aid, that seems like a big “if”.
Another factor here is capping. The UC System recently capped non-resident undergraduate enrollment at each campus. Four campuses (UCB, UCLA, UCSD, UCI) have already hit their caps, so non-resident admissions are likely to become increasingly competitive there in the future.
But UCSB was still well under their cap last year (13.5% non-residents vs. 18% cap). So they currently have a “green light” to enroll more non-residents. UCSB and UCD are probably the most attractive campuses that are still below their caps (although UCD is getting close). So it would make sense for non-residents to target UCSB specifically.