The weapons carried by police in Canada is an arms race they didn't start. For most of my patrol career I carried a .38 revolver which, over time, left the police disadvantaged, in terms of stopping power, round capacity and reload, so they moved to semi-auto pistols. Similarly, there were many incidents where the police - particularly rural - were confronted with higher powered weapons at longer range; hence, the move to patrol carbines. Large urban departments have somewhat of an advantage where dedicated specialty teams are close at hand and most often already on duty and available to respond. Not so with deployed or smaller departments where this type of assistance can be hours away.
Even in the UK, that everyone wants to hold up as the gold standard of unarmed policing, there are currently discussions whether to generally arm-up. The Police Service of Northern Ireland, and a couple of others, are already fully armed. I don't know if these discussions will lead to any change but at least it is being debated.
With regard to the 'Buffalo incident', it was clear to me on a video that the victim was holding a smartphone. No doubt it was even more clear to the officers. I am reminded of TPS Cst. Lam during the Yonge St. van attack incident. He was similarly confronted with a smartphone, being pointed to mimic a weapon, at a close but longer range than in Buffalo, but was clearly able to determine that it was not a lethal threat.
I rarely comment on police action that I see on the news. Short answer is 'I wasn't there', but it strikes me that what took place in Buffalo was not only wrong but ineffective. Assuming the goal was to enforce a curfew or clear an area under a lawful order, at first contact with the public (the injured victim) the line stalled. Actually, the group of officers walking on the sidewalk wasn't even really a line, more or a group. I never was a public order/crowd control member, but would think the proper procedure would be for the line to quickly pass any detainee to an arrest team following behind.