Not really. If people don't know how to import a very common file format used by thousands of users, such as used by Openbox, then people can't use the program. The goal of any new software program is to get the maximum number of users quickly to get the word-of-mouth publicity. Also, the presence of errors popping up gives a sense that it is troubled software. One quickly starts to wonder if there are other unfound problems. I guessed that "microHD" might work when importing; others may not guess correctly since there are dozens of import formats listed.
For the final release, if that error still occurs, it is a bug. Once software imports a file format successfully (as it did), it should be able to save the data in its native format (.si in this case). Having said that, I guess one needs to export to microHD format anyway to be able to load it back into the microHD to use after editing. Beta testing is to find bugs. Final version shouldn't show errors if reasonable actions are being taken.