It's not a secret at all. Streaming services charge money for many additional services. This is the first and main rule for which I dislike them. But there is an even less obvious point. You should always have internet. I am a person who travels frequently. I have a regular mp3 player and fill it with Mp3 Indir Dur. Such an online service has a lot of music in its library. All this can be openly downloaded without registration and payment. I was often asked about this, so I took the liberty of answering in the general chat to everyone.