On short flights a quick announcement might be whats required, a high workload in the FD can make a PA tough to fit in.
YYZ, yes I know what you mean!
Reminds of the joke (allegedly) of the a/c going from LHR to LAX (10 hour flight). Not a word was heard from the flightdeck until 5 hours after take off when a voice came on and said "HALFWAY" and that was the only PA heard from the flightdeck during the whole flight!
I did travel on a certain loco from EMA to BCN a little while ago. The clarity of the PA was good but the delivery was, to say the least, awful. Every phrase included the "er" and did little to convey confidence! I know many operators give training in use of the PA but others do not do so. When I first started flying (in the 1970s!) I used to write down exactly what I was going to say before pressing the key on the mic! That way you have time to think about it and, hopefully, the delivery is more impressive! Then after a while I was in a position to "ad lib" a bit more having listened to certain Captains and copied what I thought was good and deleted what I didn't like!
But if nobody tells the Flight Crew that the PA is inaudible they probably won't know. As crew I know that if somebody tells me then I can put it in the Tech Log so it gets fixed. Also there is a safety issue if the PA is inaudible.