I would encourage you, not to limit your writing to one genre. While many writers find a particular area that is successful, it’s good to stretch your writing muscles by writing something totally different. This doesn’t have to be seen by others, but it will help improve your writing.
Authors may publish under two different names for marketing purposes, but they write other things. It’s similar to a comedian playing a dramatic role, or vice versa. This helps you to realize you can accomplish even more than you think.
It also helps keep you, as a writer from being bored. A bored writer can bore their readers. Bored readers will look for something else to read. Readers who a writer, excited by his subject, will stay to find out more.
This is the same reason they tell people in leadership training to read books outside of their area, it provides perspective, newness, and it fuels us forward. This is true of leaders and writers, both in reading other genres, as well as writing them. Exploring other areas of writing will enable you to write better in all areas.
Mental stretching in writing has the same benefits as physical stretching before running. It allows you to write what you want, in a better way, by trying your hand at other genres. While it’s good practice, it can also lead to discovering that you enjoy writing other things.
Either way, it will benefit both you as a writer, and your readers. If you want to write a novel, try writing a 500 word short story. If you are a short story writer, practice writing a poem. Stretching your writing will stretch you, and help your writing go farther, faster.