CD vs MP3

Sometimes I listen to CD but always listen MP3. Because I have MP3 player and CD player but MP3 player is more light and has another punction like watching video. But I like to buy CD. I can't decide what is more resonable or better there are different sides of these way to listen.
First thing is about price. People who don't buy CD think CD is more expensive and MP3 is cheapper. But before compare these two, think about what you expect. people like singer's fan they look for of course song but they look for their star's picture or some other things. So it's case by case. It depens on who gonna buy CD or MP3. Not like their fan, other people expect singer's song and they don't need picture or other thing. So they are convenient without other thing.
Two is about What I like or not. In CD there are about 12 song and singer's sung one or two song like Teenage dream and firework belong to Katy perry or Blow, Tik Tok by sung Kesha. Almost two song is known for their title song in their CD. I like to listen whole songs in CD in the case I like the star. I can find really good song in their CD better than their title song. But MP3 have also good aspect. Somethimes I could hear songs I couldn't like I really wish erase those song but I can't do that. If I bought MP3, I can hear about 1minute befor I buy songs so I can find what I like or not. So there is no happening about the song I like or not.
Final thing is about convenience. I said befor CD player is heavier than MP3 so MP3 player is more comfortable to move. And CD player have just one function which listen to music but MP3 has changed now have many function like watching video and reading books and playing game. But CD player's sound was better than MP3 player but now technology has developed, MP3 plyer's sound is similar to CD player.
I can't say what's better or not. One of my friend always keep CD player in her bag. She said that's more listen to music. I have both CD player and MP3 player. Always I have MP3 plyer and sometimes listen CD player but I like both.