No, random people should not try to get into gun battles to protect their phone. If you're that worried about the rare chance of being forced to unlock your phone by criminals you can limit which financial apps you have on the phone.

Despite some popular fantasies, buying a handgun and shooting some targets (or live pigs?!?!) does not turn one into an action hero. That kind of escalation is likely to get the phone owner or another innocent person killed. It's a stupid risk, especially given that there are much better ways to protect your phone data.