What is really the purpose of streaming??

What is really the main purpose on streaming?? Is it just a big convenience to have music and artists at your fingertips? Is it that you get a better sound than cds? What if you have a cd player with an exceptional DAC built in like the Rega Saturn R . To me when cds came out i never looked back on my LPs. I thought cd playback was the best. Now i hear alot of streaming talk. Can someone clarify this to me ?