My view is the enclosed hammer snub revolver can do certain things no autolader can. IMO, there is no more effective firearm in the context of extreme close-quarter/handgun combative type scenarios.
When out and about, the situations I'm likely to encounter and have no other choice but to engage will be reactive close-quarters. I'm fairly comfortable with carrying a snub in such instances. Odds and the stats back me up.
Home defense I view very differently. Avoiding and/or leaving isn't usually an option. Since I'll have to make a stand and defend my family, I like to have high capacity weapons available, although a snub is still better for certain circumstances where a close-quarter struggle is likely. I have seen a few civilian home defense involving a high number of rounds fired, but not so with concealed carry in public. I'm talking absolutely necessary defensive responses rather than proactive engagement.
These terrorist/active shooter incidents are high profile and get a lot of media attention, but they are still astronomically rare. You have a better chance of getting struck by lightning. Would you feel the need to strap a lightning rod on your back after seeing a news story about someone getting struck by lightning? The most effective response to an terrorist attack/active shooting would generally simply be fleeing the scene as quickly as possible, but it ultimately depends on the precise circumstances. Close-Quarter defense scenarios are not rare and preparing for them should take priority in determining our gear, weapons and the bulk of our training methods.