Define intensive. But any well architected app that wants to work well without Internet will write many things to disk. 500 writes a second is very realistic

Define intensive. But any well architected app that wants to work well without Internet will write many things to disk. 500 writes a second is very realistic when downloading some bulk content that will be used to power different states of the app. Now this might not be a continuous burst of 500 operations a second sustained, but many it has a handful of these bursts over several minutes. Given that, I would say that lots of mobile apps can have brief periods of tons of writes.