SAAS is also an acronym for Software As A Service, a method of monetizing software delivery to end users without requiring them to build out an infrastructure to support the new endeavor. This can save a company money, but there are several pros and cons to the concept.
Some of the pros include fast response to outages, since the hardware is controlled by the software company, with entire teams of product experts standing by in case of any issues. They also keep things updated and roll out security updates such that they're transparent to the end users.
Some of the cons involve issues with connectivity between the businesses. If there is an outage with the user company's internet service provider, there is nothing the SAAS company can do about it. If the software was in-house, it could still be used to do things like take orders and data entry, but whole departments may go down when someone at the ISP screws up a single line of code in a router.
It all comes down to what the company purchasing the service is willing to deal with... taking care of the back end infrastructure or putting up with an occasional outage and not having direct control over their data.
Iron Noder 2017