Just like pepper spray and mace, bear spray often backfires on the user, causing them to be incapacitated.
A firearm does not do that.
Bears do not disarm you and use your weapon against you.
Firearms - 1
Bear Spray - 0
Often.
Sounds a bit like Russian Bear Roulette.
Biggest fools of the Bear Spray were those who, several years back, thought it was a bear repellent and sprayed themselves down with it.