I won't pretend to know all about the various vacuum systems on the many choices of housings out there. I shoot Ikelite (for decades and now a Canon SL1 housing) and have never installed one. As recommended for all housings I check the tightness of control fittings, push buttons etc. usually on dive 1 after flying to a destination.
Any opaque housing likely benefits from a vacuum system depending on how familiar the user is with pre-dive set and checks. But they aren't perfect as even some other posts on leaks and floods have previously detailed.
The only other thing I'll say is John at Buddy Dive has more experience seeing all manner of housings and extras than the total community here. So I think someone who's seen what works and doesn't work probably has a better real world view is all.
If you love your vacuum system and it works for you that's fine. But likely thousands of dives are (were) made for decades without them. So it's usually in how someone was shown to set their system up and then followed that procedure being most important.