I've never seen a saas product that isn't using and/or "sharing" their customer's data for their own benefit somehow. If they exist at all, they're the exception and not the rule.
Saas seems a lot more predatory and risky than most products/services. You hand over money, you hand over control, you hand over your data and all of it leaves you varying degrees of vulnerable.
I guess I shouldn't expect a pragmatic view of saas to be popular around here (some of you are likely working on your own saas projects after all), but the reasons saas is attractive for companies to offer are the same reasons that make me hesitate to use them.
FHE does have potential applicability here, but i think the potential is a bit overblown because there are a lot of devil in the details issues.