It's MUCH easier to manage SaaS across multiple user (client) systems because the local IT shop doesn't have to deal with issues like applying patches, security updates, etc. User turns their computer on, opens the software (which connects to the externally-managed service, and does what they do. No muss, no fuss, no media to manage, no way for one system to be out of date or configured differently from someone else's...
From an IT management perspective it's great. From a software vendor's perspective, also great: continuing revenue from subscription sales and ongoing renewals, no media / downloadable files to distribute... it's only the end users who suffer. Who really cares about them, anyhow?
