When this was written, iOS 8 was unannounced and folks generally just used localStorage for cross-browser storage. IndexedDB isn't as high-level as some folks would like, and key-value is handy for many apps/sites.

Even with iOS 8's support for IndexedDB, there are edge cases in different browsers localForage handles, and it handles storage of Blob data and TypedArrays transparently too, which is handy.