My argument in support of the general immersion concept but against AJATT is that most people can't actually effectively use that method without hitting a wall. The amount differs for everyone but after some ratio (say around 50% of your waking hours) your brain will stop working as well and you need space to process what you learned. Finishing a long study session (say listening to a few YouTube videos then having a session on iTalki with a tutor, etc.) and having my phone in Japanese just sounds like hell to me.