It was an experiment.  First having a power down of over a year which didn't work and allowed those with comparatively large funds to draw enough out each week and keep the middle class and poor people from being able to dump as fast.   

Why do people keep Bitcoin, Litecoin, or ETH when the price goes up?   Because they think it is going to go higher.   

The power down helped nothing and hurt everything.   Kept investors away because it was too risky to lock capital up.

The long power down time is actually a disincentive to keep Steem powered up if all you're doing is speculating on price.  With only 3 days to power down, you get the best of both worlds.  It's long enough to prevent panic selling and short enough that speculative players may be interested in powering up when they weren't before.  This should serve to increase the value of Steem.  That is, if Steem is still around for much longer.  It should be interesting to see what Mr. Tron does now.