Vanya,
You have to ask yourself, do you want a publisher to "practice" with your book?
Many successful small publishers have some experience in publishing before they hang their own shingle -- even if it's just publishing their own stuff for several years before they open their doors to a few selected authors and then once they have that experience under their belt, then they open it up for general submissions. The smart successful ones have a limited number of books they bring out a year and usually a very narrow scope of selected titles. This is so they can procure, edit, and market the books they pick up properly.
If a publisher who only sold m/m romances suddenly branched out into something like cozy mysteries without any explanation, I'd be worried that they didn't know the market, didn't have editors who really knew what made a good cozy mystery, didn't have the marketing force to promote these books enough to rise above the signal-to-noise ratio. That's why most smaller presses specialize in a few genres instead of being all inclusive.
Unfortunately, too many new publishers remind me of the old Mickey Rooney movies -- "Hey, I've got a barn, you've got a piano, let's put on a show!". And, you know what? If you're ONLY working with your own stuff, that's cool. However, when you start accepting books from other people, you assume responsibility for their books too. That is NOT the time for amateur hour.
What is the press bringing that you can't do for yourself? Does signing with them give you a bigger footprint? Does signing with them (and giving them part of your money) get you a better editor? Does signing with them get you a better cover artist? These are questions each author needs to ask themself before signing with ANY publisher from Random Penguin all the way down to the smallest publisher.