Don't understand why anyone apart from staying legal would want a bell, it just promote the aggressive cyclist image, get out of my way, coming through, whats wrong with slowly down & asking people to move?
On a shared path, if you get one with a nice 'ting' and use it from some distance, it alerts someone you are coming, then if they don't hear you, you say 'excuse me can I pass'. I didn't use one for ages, but the trails are quite busy at present, and it's nice to give a little warning. I also ting before I go through a canal bridge, as they are 'blind' turns.
If you ding ding ding, then yes that's aggressive, or ding when you are right next to someone - advance warning always helps. Especially extending dog leads or half deaf pensioners.
I ding'ed at a group of 4 late teens (not socially distancing) yesterday, from a distance, no acknowledgement, then 'excuse me' again no acknowledgement. Now I was coming down a loose stone track, so the MTB wasn't quiet across the pinging rubble. The girls only bothered to turn when I locked my rear wheel up slightly (deliberately) after 2 warnings. I was still 50 foot away. They moved but the two lads didn't - you can't win.
I did "ding ding ding" to two yoofs on MTB's completely blocking a bridleway last week as I'd come off a descent at a fair lick, they were 100m away, but weren't shifting. I even said 'coming through'. They eventually moved. I wasn't stopping as it's under a motorway bridge and near "rough ville".