You sort of asked two different questions there. Generally I don't torrent music these days, though I have done in the past (Audio-4U, for example). I do use P2P methods like Soulseek for some stuff but predominately I rely on direct downloads through DoujinStyle.
In terms of why I pirate, it's because I can't afford to buy all my music and streaming services offer inferior quality, catalogue size and revenue to the artists. I'd rather manually curate my own offline collection and put the money I would spend on a streaming subscription directly towards an artist whose work I particularly liked whenever I can afford to do so.