I think that's just their way of making sure they don't lose track of where their possibly still very buggy software goes so that they can get the feedback and tell their users when it's time to upgrade.
The differences with CUDA are so small though that it is fine to develop for CUDA now and upgrade to OpenCL when they release it publicly.
http://www.nvidia.com/object/cuda_opencl.html
I think that's just their way of making sure they don't lose track of where their possibly still very buggy software goes so that they can get the feedback and tell their users when it's time to upgrade.
The differences with CUDA are so small though that it is fine to develop for CUDA now and upgrade to OpenCL when they release it publicly.