a music thread! I'll post a slightly different different perspective on why learning covers is better than not, if you are able.
emulation = learning
the fastest road to learning in my experience. Prior to learning covers, I spent all my practice time doing scales and patterns to a metrinome. snore. great for hand coordination, but lacking in getting the brain working. Then I tried writing songs, and would get lost in song structure. I know there's an intro, hook, verse, chorus, verse, bridge, some foolery and a solo in there somewhere, but man o'live... once you get into writing the song, it's a never ending battle completing it, because none of the parts ever feel "complete!".
ability to entertain at parties
Ever been to a party with other musicians? Or flying solo? With other musicians, if they say "hey, let's jam!.", you can do just that. If you don't know any covers, you end up saying "um, I don't know any covers, but I wrote one?" okay... so you spend an hour learning a song at the party so you can play it?...
covers are ready-made. Had I said "I know these 25 covers", chances are, instant fun! And all those people at the party will likely know them and be able to participate - sing along! dance, whatever.
Great guage of musical ability for yourself
when interviewing a potential band member, or even knowing what your own abilities and limitations are. When I started learning covers, I realized there are a ton of licks, riffs and chord progressions I wouldn't have likely never learned because I was under the impression that if I heard them on the radio, surely I must know them! But unless you try them, you're poorly mistaken when it comes time to implement them.
Covers are a good guage of potential band member ability
Interviewing a guitarist? A bass player? a drummer? They didn't really come prepared to learn your songs, but they assure they can learn and play the song! The person's there, you scheduled him/her - so you may as well give that person a chance on the off chance they're not pulling your leg. I know, they broke the golden rule "come to the audition prepared to play", but let's just say you met him on the street and he fed you a believable line and you're interested. You can test the musician out with
"Let's warm up with [insert a cover song every musician should know]".
Just a few reasons that came to mind when reading this thread.
Personally, my ability as a guitarist/singers has really grown by doing covers. I've learned what I can and can't play/sing in a live situation doing other's materials. It really helped me with self-introspection on where I'm at musically, and what it takes to learn someone else's original song from start to finish - all the nuances you don't think about until you're forced to play them included.
Chris