It's not about boxing you in to anything musically or identity wise. Its about finding the quickest easiest way to communicate the essence of your identity to your potential audience and the music industry folks who will help you reach them.
Because the record business fell apart by not keeping up with the new technology there is no more money to support an act through a period of development before presenting them to the public. This means the onus is on the artist (and the team they are working with) to focus on the best way to market the music to their demographic.
Trust me there hasn't been an important meeting in my career in the last few years where the industry person hasn't wanted to know what I think my artist identity is, what I perceive my demographic to be and how I intend to market my music to them.
Finding the answers to these important questions is a process of trial and error. First step would usually entail playing your music for everyone within your reach, both music professionals and regular folks and asking the questions "who does my music remind you of". Why? Because as much as we artist hate being put in a box, telling new contacts what other artists we sound like the quickest easiest way to communicate who we are.
"People say my music sounds like a cross between Sheryl Crow and Bonnie Rait" is a useful tool. In one sentence everyone knows exactly what "world" you inhabit as an artist. It starts to suggest your demographic and the various creative ways your music can be marketed to that demographic.
In todays climate every artist is expected to have at least a working knowledge of their brand and how it fits into the marketplace. Start asking questions and formulating the answers. This is a process that takes time and lots of trial and error before hitting the nail on the head.