For me, I'm trying to reduce the number of total files in shared network locations. Utilizing the mobile geodatabase is very attractive because it is a single SQLite file as opposed to the smorgasbord that is the file geodatabase. If the mobile geodatabase is the future of local database storage, then this should be an option you're able to toggle within ArcGIS Pro.
The implementation of the mobile geodatabase is not complete, just as the file geodatabase is never complete (eg an elementary thing like involution is not supported even after 16 years of fgdB development). In the current state Mobile gdB does not support eg raster field type, rasters dataset and mosaic (very important for every GIS repository/data storage). Externally, with the help of an SQLite manager, you can load raster data as Blob datatype, but it will be invisible and unreadable in AGP. Also, you cannot edit data loaded into the mobile gdB through AGP outside of AGP. ESRI has, therefore, reserved both types of databases for itself, but does not do much to implement them for users as a personal and local replacement for large RDBMS (but ... by the way, other players in the GIS arena are working even less on this). All in all, this idea can only be acceptable when ESRI implements all of the above, which I doubt will ever happen.