From what i've been reading it looks like Fast Pass+ is being tested for Lunch at BOG. There are no ADRs available for BOG for lunch- only dinner. Getting a dinner reservation there is tough. So the advantage to a lunch fast pass+ would be not having to wait an hour to get in for lunch.
I saw on the BOG lunch testing site that there was an option to preorder your food as well. If you have little ones this could be very useful. You show up at your time and your food is ready for you. Nice.