Ok, I have some input.
While a single suppressed shot may not be distinguished from a car door slamming or something similar, many shots in quick succession, no matter how different they sound from gunfire, are often discerned as so from pretty much anyone with half a frontal lobe.
I say, 'it depends...'. Yup, if that's not a non-committal answer, I don't know what is.
While I agree with the benefits in the OP, let's explore the negatives:
For Rifles
-A can is heavy and adds length. Any fullsize can will really really upset the balance of a, 'fullsize' (read: 14.5"+) when used offhand. If it's an SPR-ish gun, used on a bi-pod, well, six of one and a half-dozen of the other... on a 16" or 14.5" gun, no bueno. So, SBR's are better for cans. However, the shorter barrel means a reduced longevity of a can and the ballistics thereof. New(ish) reflexive cans mitigate this but they don't suppress as well.... they kinda, 'take the edge off', if you will.
-More lubricant needed, as posted about. This can really really be controlled by coatings (such as FZ, which I am a big fan of)
-Harder on parts due to increased back pressure through has system and barrel. This means just like it says: Parts won't last as long. Period.
-Shit in your face also due to increased back pressure. Very distracting (especially during FA use)
For Pistols
-Doesn't work with every setup. Cans that have LID's (google it) will do better but others require more testing for reliability
-Gas in the face still can be a problem with pistols
-Lack of holsters. Like seriously. I can't think of a possible, 'Tears of the Sun' moment, hence why there is no longer a suppressor carrier on my rig...
My main advice is the same given to ODA teams: either run it 100 percent of time or no percent of the time (outside of special application)