Yes, the software supports ISO files. This information can be found on the description posted by the developers on their website.
"Macgo Mac Blu-ray Player is the first Blu-ray media player software for Apple Mac, which can successfully play Blu-ray Disc, Blu-ray Menu, ISO files, and BDMV folder, as well as on iOS devices." - Official website
If you have Blu-ray movies in ISO format, simply open the software and load the ISO file and the playback will start accordingly.