You will find that the majority of well know bands played covers before venturing into writing their own material for example Pink Floyd,The Rolling Stones, The Beatles, Led Zeppelin, Deep Purple,Eric Clapton I can go on forever.
The Idea of playing Cover songs is not necessarily to cover the to the letter unless you are a party type band. Listen to the Radio One live lounge and you will have an idea about what I'm talking about. Songs have been covered by jazz and blues musicians from from year dot. It's a good way of getting to Know what makes a band tick also you will find a bigger audience to support you and also a bit of cash.
I have seen so many young bands playing to empty halls or for ticket sales on the door all doing original stuff.OK I have mentioned a few of the old rockers but take it from me, old rocker or modern rocker most have played covers. I'm not saying it's wrong to want to write your own material but put some covers in with a blend of your own stuff and you will be on your way. I challenge you to do your own cover in your own style, not a carbon copy version of a band or bands that you are influenced by and you will see how challenging that is.