This is a very good write-up!

The long powerdown is an important security feature not only for chain security but for individual users as well. Suppose you leak your password and criminals get access to your funds or that someone breaks into your house and demands that you transfer your funds at gunpoint. If you're all powered up, your funds simply cannot be taken. Powering up reduces your risks very considerably. Implementing instant powerdown for a fee would be a serious mistake. Powering down should take a month at a minimum. Three months is actually pretty good.

Let's say you had millions of dollars worth of HP in an account tied to your real life identity and powering down instantly were possible. You'd become a walking target. The fact that Hive is a blockchain that has irreversible and uncensorable transactions and pseudonymous accounts and that HIVE can be swapped for other coins and cashed out effectively anonymously makes the situation particularly dangerous. Bank accounts can be frozen if necessary to stop crime. But if everything is powered up and the powerdown time is three months, potential kidnappers or extortionists would be deterred from even trying.