On the subject of bicycle bells, I do think the idea mentioned in the OP has some merit.
That said, around here bicycles aren’t supposed to be ridden on the sidewalks, but on the edge of the roadway, and with the flow of traffic. The sidewalks are for pedestrians only. But, some roads don’t even have sidewalks, and some are rather narrow, so pedestrians and bikers have to share.
Also, the main stretch of road in the city is also considered a provincial road. So, the condition of that road is rather bad, particularly along the edge. (The amount of traffic, combined with the city and the province fighting over who pays to fix the road, and the northern climate, are the three main reasons for this.) Someone would have to ride their bike more than a foot out, and into traffic, to avoid the potholes.
Add that to the fact that the drivers around here are notoriously bad, and it’s a rather bad situation for bikers. (I personally never ride down this main stretch, but take the back streets, which connect to the main road in many places if you have to get somewhere on the main road.)
The bells on bikes idea, however, reminds me of my idea that all cars should have two or three different horns - a rather innocuous beep to say hello to someone, a louder shrill horn to warm someone, and maybe a longer, staccato noise to tell someone off.
Okay, that third one may be unnecessary - people aren’t supposed to blow their horns without reason - but it sure helps to relieve tension while driving. (I personally rarely use my car horn. When someone ticks me off, I simply curse aloud, but never let things really get to me. I don’t get angry if something simply annoys me.)
Anyhoo…