Originally Posted by MaximusJ
when the angle is ackward
Pretty much this. An articulating screen is great if you're shooting from odd positions and/or angles. With one, you're not relegated to using only the standard viewfinder or angle adapter. The articulating screen provides more freedom in that respect. They're come in handy from time to time on my advanced point-and-shoots. That said, not everyone shoots in such manners. For those that don't, there is no need for one.