It is entirely possible to make a MKV or MP4 whose video and audio are already compliant to Blu-ray specifications. This is easy to do in quite a number of different software programs.
The problems start when you want to author to Blu-ray format AND have a menu to select several different videos without re-encoding either the video or audio. For this you need a pure authoring program, and the choices are not good for amateurs. Most of the pure authoring programs are very expensive and have capabilities beyond the needs of most amateur users.
If your program had the option to pass through compliant video and audio, it could be used in this manner. But unfortunately, you do not offer this ability. This is a shame, and a wasted opportunity to make your program stand out from the rest of the Blu-ray conversion programs.