1. Turning them on/off ala bumblebee isn't a solved problem. It's buggy, especially on not-windows. Even on windows, it's going to be buggy especially in regards to sleep.
2. You obviously lose the advantage of a nvidia GPU that way. If you have to always have it off to get decent battery life, which you do, then it's kind of moot. If you turn it on for your 30 minute workload then there goes 70% of your battery.
You can, I just think it's inconvenient so I favor laptops with better battery. Besides, I almost never find myself being on the go and needing a dedicated GPU.
