Especially since the established collections prefer/require first publication. Why should we risk that you'll publish and fail to pay?
Lining up those SFWA ducks will be important. At that point, even as a new publication, if they're easy to work with, they'll quickly become a great second or third stop for fresh stories. They won't get first submissions for awhile, because you can't compete with Terraform's (and others') 25c/word rate. But that's okay. Gems fall through the cracks. Loads of great fiction out there looking for a home.
Obviously, the publisher needs to be discerning in what he actually buys. But if you're a writer trying to build a relationship with a new publication, I don't see any problem recycling work that didn't quite hit with some of the established markets.
If you're unpublished, or you've only been paid lower rates, you probably shouldn't be asking the question "Why should I submit here when I can submit to XYZ?" You should just tack the new publisher onto the end of the list, and when you've worked your story through the others, drop it here before it hits the trunk.