Unified Communications (UC) was a nice label for the mashup of voice and data networks, but for most organizations the move to UC was driven by a desire to reduce audio conferencing costs. This is what drove many business cases and got the CFO to approve UC projects.
Then came “the cloud,” which shifted large upfront capital costs to recurring monthly expenses and eliminated the need to deploy and scale, complex, on-premises equipment configurations. Because services from the cloud are expensed as incurred and can be scaled up and down based on need cloud-based UC provided cost optimization that made CFOs happy, flexibility which made IT leaders happy, and rapid access to features which made users happy. This drove an explosion of UC offerings.