Why would I turn my bitcoin to steem and lock up for 3 months?

For security reasons. To be honest, I prefer to keep it in my Steem wallet more than anywhere else, because I know that then it can't be hacked/stolen, because it is technically impossible (through Steem's inbuild account recovery features).

Why would you think 1 week power down is insane?

How should account recovery work with a 1 week powerdown period, when the whole recovery process is based on a 4 weeks period? Just disable all security on Steem to be able to receive bucks quickly?

Big investors don't make short term decisions. Most of them are in for years and they don't care much about market price fluctuations in between.