You are there in the studio to capture the creative performance, and you don't need barriers to the creative process.
There are endless benefits to focusing on your instrument, your arrangement, your music.
Having to focus on the recording aspect of things like mics and gear creates a barrier that steers your energy into the technical side of the process.
Recording engineers can eliminate the barriers so you can be free to create music.
So - why use a recording studio?
> For creative freedom and a better flow of musical ideas!
Paraphrased from an article in Sound On Sound's "Sounding Off" April 2011 (USA edition)