Hello JD,
I agree with your assessment. I use the split-tone to create a web-version of an image and to assist in visualization of what is possible and most likely to meet my vision of the final output. I do print the grayscale file through IP with the spit-tone capabilities inherent in that software. I have found that the LR spit-tone is not always clean as it can have some unusual tints in transitional tonal areas. I have seen some greenish tints in such areas. I have mainly used the Mac beta to date. Like you, I am not sure that the split-tone is fully ready for my BW printing workflow, but I will continue to investigate and will probably do some head-to-head experiments with printing directly from LR to printing through IP. Good luck and take care.