Slob knobs are a triumph of practicality over snobbery
PS my CCR instructor dived Alpinist but I don't. Two of my GUE instructors dived without a slob knobs and my Tec instructor for OC dived a CCR but If I dive twinset OC I dive a slob knob
Diveing without a slob knob put far greater pressure on buddy skills buddy diveing and "team work"
If you don't use a slob knob chances are you will have less gas to paly with and will need your buddy more. SO Slob knobs are ideal for the way I dive which is solo with another diver for company who I expect to let me down in an emergency and if they help that's nice but I dot rely on it.
SO qualifie your opinion.
Manual shut down are ONLY good for people A: who find them easy and B: for people who dive in skilled disciplined teams.