But one‘s personal time is worth much more than ten dollars.
It a more efficient use of this time to solve a problem once instead of solving it on each platform separately.
You get a text file (if you export it). The format is cross-platform. You could make the initial in Monodraw, export it as a text file and delete de monopic file so you get a cross platform format. Editing will then be cumbersome.
You have an exported text file. While that may be cross platform, as soon as it is modified the monodraw file is no longer the source of truth for the diagram and the advantages of using it in the first place are lost or require someone to go back and update the original and export it again (and move it through the workflow).