My experience with DL
I used DL in order to improve my Spanish knowledge. I bought a couple of CD's and listened to them in the car, on the bike or at the weekends. A great opportunity to fill time which otherwise would be lost.
To really learn a language it is inevitable to speak. DL tools help you understand but they do not actively interact with you, The exchange of dialogues is missing and a big disadvantage when it comes to learning languages.
One can learn anytime and anywhere. I always have some sort of e-book with me.
Listening to foreign languages helps improve your language skills, especially when you are just about to start the process.