Simple PBX style operations, call routing and voice mail are handled "out of the box" and it's drag-n-drop easy to create TwiML based applications. Within minutes users can create dial-plans, IVRs, conferences as well as send and receive text messages.
VBX simplifies the Twilio process for many (but certainly not all) business-line use-cases of Twilio.
For developers & engineers the system moves the burden of tedious phone-system operation to a hosted service. This allows you to focus on the cooler parts of the operation - integrating with the core business applications and building the systems that make the money.
Check out our Chrome Extension in the web-store.