You are right that process sandboxing is not as important for Servo, but it is important: 1) more defenses are more better, 2) Servo contains considerable amoun

You are right that process sandboxing is not as important for Servo, but it is important: 1) more defenses are more better, 2) Servo contains considerable amounts of C and C++ code and will for some time, 3) Even safe Rust has failure modes that can abort the process (primarily out-of-stack), and multiprocess provides recovery for when they happen.