iPhone apps are about to get much more sophisticated
Previously, apps couldn't exceed 2gb in size. The change bring Apple in line with Google, where it's been previously lagging behind. Google upped the size limit for Android apps on the Google Play Store to 4GB 2 years ago. (Even larger Android apps are available if you download from third-party sources, something iOS users can't do.)
The change isn't needed by all app developers: Many of the most popular apps clock in at much less than 2gb. Twitter is around 100MB on a clean install, for example, and Snapchat is just 24MB. But for media-rich apps and games, the size increase will allow for for the inclusion of far more content. Apple says the change will allow developers to "include more media in your submission and provide a more complete, rich user experience upon installation."
Games in particular are already bumping up against the 2GB upper limit - GTA: San Andreas, a port of a PlayStation 2/Xbox game, is more than 1.6GB. As such, the graphics and size of games could improve markedly as a result of this increase.
But the size increase also highlights the issue of storage space on Apple devices. The cheapest current-generation devices are just 16GB (although Apple's website also still sells the 8gb iPhone 5C); Accounting for iOS system files, users would be able to install just 2 or 3 apps utilising the new maximum file size.
The cellular delivery size limit remains unchanged, however, at 100mb.