I totally agree! Shoulder rests and chin rests are only there for the players comfort and to help prevent injury. What works best depends on your unique body. Although, I’d suggest experimenting with chin rests first and then find a shoulder rest to match. Especially for people with long necks. If you have a chin rest that’s too low, but keep lengthening your shoulder rest it will cause the whole instrument to become too high and will cause your right arm to get out of whack. With a taller chin rest, it will cause the neck to be less bent over, resulting in less overall tension in the back of the neck. It also does not affect the position of the violin in relation to your arms.
If you have a really short neck, you want to look for a short chin rest and you don’t need to lengthen the shoulder rest as much. You can even try going bare back if you find it does not affect your ability to shift.