It's a good thing for investors to be able to pull out their stake at any moment (and by the way, still 'earning' on that stake through inflation... Wow.) - The other side is scarier though, there's no guarantee that even though the developer holds its promises the investor won't pull away the SP suddenly. We've seen it before both steem-ua, utopian, surpassinggoogle, have temporarily or permanently lost huge chunks of SP very suddenly leaving them in doubt if they would get it back or having to explain to their projects participants why upvote values suddenly dropped. I see dstores now rewarding 'per 6 months': they will reward SP delegators only if they completed the 6 months. But what if after these 6 months all delegators undelegate? There's a huge inconsistency problem there.

I see Partiko being smart as well: they are collecting dozens of smaller delegations, making the risk of a sudden drop in delegations smaller. Another reason we need a bigger 'middle class' of SP Holders.

Anyway, just a few smaller worries that we might see solved through creative ways of rewarding, the overal concept of 'risk-free investing' is mindblowing - hopefully people will soon start to understand the huge opportunities that lie in that.