All the time. FaceTime is a prime example. I get up and walk around. I don't just sit staring at the screen and never move. Furthermore, if you have more than one person at one end of a FaceTime call, at least one of you is already off axis. Also, if I'm watching on say a plane or with the thing on my lap, it's not always at a perfect angle. Remember, it's not just about left/right axis, it's also up/down axis. VA is generally just bad.
It's just too much of a compromise. The reason it works in TVs is because generally you sit further back and try not to be too far off axis, and for relatively extended periods. Tablet use is a completely different kettle of fish.
It's no surprise that Apple uses IPS LCDs even in its $299 iPads. Going to a different tech with poorer viewing angles would be a huge step down.