After reading quite a bit on this and other camera implementations, the bluetooth appears to only be a constant bridge between your camera and your phone/tablet. As you want to do things with the camera from your device, those commands occur over the bluetooth connection. When data instensive things are needed, then the camera will turn on wifi for you automatically, connect to your device (provided you had it set up before), and then do the functions, and later turn off wifi to save battery life.
So the only time saved here is that the camera will automatically turn on/off wifi for you as needed depending on the functions you want to perform, while always staying connected via bluetooth for command and control back and forth. You no longer have to turn the wifi on/off yourself as you need it;with the bluetooth addition, the BT connection does that for you automatically now.
There is no wifi wakeup or sleep, there is only wifi turn on/connect and wifi turn off, so the lag involved in these functions still will exist.
Best analogy I could come up with would be two people are trying to set up AV equipment between two remote points, and instead of using AV equipment to communicate, they use walkie talkies to communicate timing and need between themselves, and those commands sometimes require AV gear to be turn on/off for video/sound feeds. The walkie talkie is the BT connection, the AV gear power up/down and transfer between two points is the wifi. Before the use of walkie talkies, there was just one person and they had to walk back and forth to turn things on and off as needed, or leave everything running all the time using up power.