I use mine for quilting. I have the Block Fab app. Also Quilt Fab and the Robert Kaufman Quilt Calc. They come in handy for calculating yardage. I downloaded iQuilt which seems to be similar to the quilt calculator but haven't yet figured out how to use it. Then I have one called Fabric Journal, although I think it should be called Quilt Jorrnal. And I've downloaded a bunch of podcasts that I listen to while I'm sewing. I like the Pat Sloan ones best.
Go ahead and get one. You'll find lots of uses for it.