What is really the purpose of streaming??

I asked because i was not sure what it was all about. 

OK. Enjoy those same old cds!

What I like about streaming is as many here have mentioned, the access to literally millions of albums. I like to read through the music forum here and get ideas for new music. For example, one band that seems  popular from the classic rock era, tattoedtrackman, is Camel. I'm not really familiar with them yet I have access to their music and can listen to different albums without having to purchase them. This is a great way to explore new music options conveniently at my fingertips.

I'm not sure what the OP means by "purpose" of streaming, but one obvious advantage of streaming is that it gives younger music fans immediate access to vast amounts of music that would have otherwise taken them large amounts of money and years of time to accumulate.  Back in the 60s I would have loved to have had a multi thousand album collection of rock and pop records for $10.  WOW! 

If i like something i would rather just buy it on cd. And they are mine to keep.Not renting songs.

The beauty is there are more choices for everyone. But it's a subscription service - a model which is being adopted by many internet/software services. Back in the day I never thought of it as "renting" a newspaper because there was a new one coming tomorrow. Except this is better because you can keep your songs tracked at your finger tips.

I have physical media and now its all stored. I went throught the ripping, acquiring, curating and storage media anxiety stage. Now I figure I'm free of that part and have more time to enjoy the music. More choices for everyone, it's awesome!