Actually there is an advantage over having a switch like this, it eliminates pilot error which would be a cheat of sorts - by which I mean, in the sabre, if you apply the AB in say a dog fight, you may forget to close it after use in the heat of battle and then get owned by the opposing aircraft, or end up in a pile on the ground, which is how it should be
with a toggle like you wish for the circumstance above would never happen and would be an unfair advantage over a player in a similar craft flying without the toggle