When I got married, one of my favorite gifts came from an old family friend. It was a recipe card that my grandmother had passed along to them many years before. Ironically, my grandmother was noted for her questionable cooking, but since she'd died several years prior, I treasured the gift.
Say what you will, you can't do that with an app.
These days, cooks might have two or three recipes we use occasionally in each cookbook we own, a file of bookmarked recipes on our computers, and probably at least a couple cooking apps on our phones. More and more well-known chefs are issuing apps, and some good recipe sites are as well.
Publishers are increasingly wondering if there's enough room in the marketplace for books, websites, and apps ... or if cookbooks are becoming like CDs, something people still buy here and there but generally prefer a digital version versus a physical copy.