why would any one hold funds in an address that they don't hold the private keys for??
for me it works like that:
Holding your own priv keys comes with certain amount of knowledge, responsibility, and RISK - that is the main trade off with trusting someone else (Iconomi). If I wouldn't trust them, I wouldn't invest.
I personally don't like the risk of loosing/maintaining keystore backups and strong unique passwords that if forgotten lock you out for good.
I don't like the idea that ether wallet doesn't have 2FA. And I don't like thinking about all that when I am long on Iconomi.
I'd prefer to have a "vault" option and that is exactly what Iconomi provides - an offline, vault-like storage service.
If funds will be stolen/hacked from Iconomi, your tokens will be worthless anyway, whether you have control over the priv key or not.