Is air integration worth it?

It is the upgrade divers stop noticing because it becomes how they dive: pressure, gas-time-remaining, and automatic SAC logging on the wrist. Whether it is worth several hundred dollars over a $90 SPG depends on how much you value the logging — the safety case is thinner than the convenience case, and you keep an analog backup either way. Skip it on a first computer; add it when you know you are staying in the hobby.