And what happens when you trip and rifle is on your shoulder?
To the OP, good points include toolless installation in majority of rifles (if swivels are too narrow the plastic part won't get through). Also some carry options like the muzzle forward, single hand controlling rifle (going through bushes etc.) It's also simple.
But I wouldn't trust the system for fast shots (rear will get tangled sooner or later). And the whole system is bandaid, fixing the symptoms not the cause. You really want multiple swivel locations, including the weak and strong side of the rifle, for versatile carry options. Also quick adjustability to balance between having the rifle secure and being able to use it fast.
Putting the rifle on your chest has benefits, but it's a total chance in habits if you're currently used to have the chest for your binos, thermal, LRF etc. You also sacrifice some front jacket pockets, since you really don't want any bulky or noisy items there under the rifle.
For short rifles and swivels on the side, I like quick adjust two point sling (Magpul, Ferro, Vickers etc.) and muzzle down on the weak side. It leaves your right front pocket somewhat usable, and you can also carry binos (or some other bulkier item) on your left side. But it's a PITA with the slings/straps interacting with each other.
There are also more elaborate slings that try to tackle the front carry with traditional rifles. Like 3HGR (tree hugger, their first product a sling that you can attach to tree) from Finland, model "Driven" is meant for (surprise surprise) driven hunt.