[monkeybutton]

Immersion provides the strongest motivation to learn and to try. When you want something or have a problem that needs to be solved and the other party doesn't speak English, you're going to be very motivated. The 'dopamine hit' from getting it right and communicating successfully in another language is also way better than from an app/game. The results are just so much more real and tangible.

[Jare]

Immersion also creates connections between the language and other stimuli (visual, emotional, etc). Connections are powerful for creating reliable memories.