It’s your personal choice on how secure you want your iPhone to be. Some people use a passcode to prevent access to their phone, others don’t as they prefer the convenience of being able to quickly access their email and Apps.
Surprisingly, in its default state Siri will override your passcode.
This means that a complete stranger could pick up your iPhone and make phone calls, send texts, send e-mails, and access other personal information without having to enter the security code first.
However you can prevent Siri from overriding the passcode:
- Navigate to Settings > Touch ID and Passcode.
- Switch Allow Access When Locked to the OFF position.
- Exit the Settings menu.
Whether you decide to add this layer of security to your iPhone is up to you. However it’s worth remembering that as Siri becomes more popular and usage increases it will attract more and more interest from hackers and thieves.