One of the most important uses for HDMI CEC is in fact to wake your TV up from 'Standby'. Why? Well almost all TV's when placed into 'Standby' mode unfortunately also power down their network interface chip too, which means you can't use IP control to wake the TV up. However HDMI CEC is always waiting for commands, and is never powered down when your TV is in 'Standby' mode - unless you set your TV to power it off in 'Standby' that is.
This means therefore placing an HDMI CEC controller behind your TV's - even your brand new SmartTV's is about the only solution to powering them up from 'Standby' under control of your system. In fact many people use our Dianemo Raspbmc-CEC software for Rpi even with a brand new SmartTV, which has in built uPnP media playback capability, just to wake the TV up from 'Standby'. Even people who have traditional Media Managers driving their TV's often use our Dianemo Raspbmc-CEC software on Rpi to send on/off commands to their TV's.
All the best