Hi dear @ciska, it is an interesting topic, reading your post I agree with your explanation . 13 weeks was real really too long, 4 weeks is Ok, but having the opportunity of 1 week is very attractable.

When we talk about bigger investors, we have to make it attractive:

First Steem blockchain is attractive as it allows the investment to grow even with simple upvotes using autobots, manual upvotes that will let them to earn without much work.

The time when they need urgently some of the invested Steem or maybe everything then knowing that it is only one week time make Steem attractive too.

At the moment there are Steem, Hive and Blurt are similar platforms, but one of the attractive difference for Steem is short Power Down.

As to hackers, there is always a risk of it, while people have invested something in Steem they must be aware at least every two days to check it. Another option while logging into Steemworld there is a warning if Power Down started. Maybe our developer could create a notification email that will let the users know that there is PD started on their account.

Cheers, @stef1