From what I've seen, a digital 3-D only release would be the kiss of death for any film... and it seems the studios know it.
Journey To the Center of the Earth 3D was intended as a digital-only release. When they realized just how few digital screens were 3-D ready, and of those, how many would be available on the day of release, "3-D" was removed from the name and a whole lot of 35mm prints were struck.
Regardless how people feel about digital or the available 3-D processes, it's going to be a problem for the studios until a lot more exhibitors figure out if they can make money off the format, AND pay the licensing fees and/or glasses costs.