"Screen time" on devices is different from screen time on TVs.
You're missing a huge part of tactile development going on when she's playing a puzzle on the floor vs. touching a flat surface. The fine motor skills involved with physically handling a puzzle will come in handy later, not to mention that there is an element of combining tactile response with mental strategy missing on the iPad.
The puzzle is a "natural" form, that encourages "natural" skills. Whereas Angry Birds is an addictive game pattern. Any skills it "teaches" are incidental to its commercial goals.
My point is invalid if the whole entire world turns into a giant commercialized strip mall and recall no longer becomes a valued skill. :<
That said, I'd say Angry Birds has given my son a lot of practice in perseverance, problem solving, and not getting frustrated when something doesn't work first time.
It can go both ways. You can either grow up as psychopath programmer or shallow creative. Either way, I bet that real social interaction is best for kids.
Obviously the key is steering them in the right direction. The challenge is doing in a way, that they do not notice being managed.
Is there any advantage to a kid knowing how to read, or write, one or two years before their peers?