Right...and I'm not sure if any iOS devices use alphanumeric. I don't use passwords on my devices because given Apple's newer password policy, it will lock me out after a few bad guesses...and lock me out for days/weeks if repeated. Imagine if I went into the bathroom for 2 minutes and my 5 year old started banging away at the passwords. Or if someone is a jerk and purposely guesses wrong 15 times while you run out to your car. I know a few people who were locked out for days due to this stupid policy.
Apple should enable an option that allows unlimited guesses like the iOS versions from a few years ago. However, a)make it alphanumeric and b)make the length be up to 16 or 20 characters.
Trying to crack a 6-10 DIGIT password will only take a few minutes or hours depending on the length. Cracking a 6-10 ALPHANUMERIC will take days to weeks. Alphanumeric passwords of 16+ would take dozens (or more) years.
Alphanumeric would be 52 letters (upper and lower case in English), 10 digits totaling 62 characters. 62 to the power of 10 would be 839,299,365,868,340,224 combinations for the machine to guess. That's 839 quadrillion guesses. Add in the ability to use some symbols and the password could be 72 characters.