[mathattack]

All very good reasons. I'll add another - accounting.

The monthly bills for small purchases of SaaS fits on what could be expensed on a corporate card. By the time IT gets wind, the product has already infiltrated the organization. If there's a very large up front cost, then IT is involved, you need a formal RFP process, lots of people weigh in, those opposed to the purchase can try and block it... As soon as "Put it on the corporate card" became viable, power moved back to the business units.

[kentonv]

With Sandstorm, we could actually get that effect on-prem. Since no technical expertise is needed for deployment, and since the security model is so strong, and the IT department will be able to manage resource quotas on a user basis rather than an application basis, it's actually entirely reasonable that people outside of IT could be permitted to install software without IT approval.

Granted, it may take a while to convince IT people that this is OK, but fundamentally they have every reason to prefer this over people cheating with SaaS.