CSIA Level 4 used to require CSCF Level 2 as a prerequisite. However, many CSIA 4s would complete CSCF 2 without actually working as a coach, so the CSIA 4 certification on its own wouldn't necessarily be an automatic indicator of success in a head coach position.
Current prerequisites for CSIA 4 include CSCF DL (Trained) or a couple of other alternatives, so the race exposure is potentially even less with the newest Level 4s.
If the CSIA 4 is also CSCF 3 coach, that's a much better indication of the background and experience that will be desirable in a coaching role.
The other side of this is that development level racers (e.g. up to K1 level - 11/12 years old) are still learning how to ski well, and a CSIA 4 can offer a lot in that area. Most CSIA 4s will also be pretty good at program management in general. For a head coach, this can be as important as actual coaching experience, and if the head coach has strong race-oriented coaches who are doing most of the direct work with the athletes, it could be a good combination.
Working as a coach, the CSIA 4 will have to meet CSCF/ACA licensing requirements, so that could also help a bit with building up the race environment experience.