[Warner306]

Yes, I'm totally aware of that but I have a few reasons to prefer disc formats like extra features, if you don't access to the full disk or a copy of it, you can't get those, your best alternative is a remux that keeps a 1:1 copy. 
Another reason is that remuxing extra contents from ISOs or BDMV is a boring process, so having the disc and access to it is much faster. 
You have to go into some site like DVD Beaver or something and check the tittle time and compare, it's a pain.

And finally, menus are really cool and nostalgic

Having a easy to use and easy of access player like Kodi supporting it would, maybe, increase the amount of users that prefer this format. 

And, I'm going to get stoned for this but at 2.5 meters away from my 65 inches 4K TV I can barely if at all see any difference from regular Kodi compared to DSplayer. 
The only reason it would make actually sense is because of it's amazing Tone mapping capabilities (specially for projectors). I honestly don't see NGU as a night and day difference for regular TVs. 

That's just my opinion and I sure do understand everybody else choosing MKV files. 
I'm actually struggling to give access to my brother over internet to my files so he can use Kodi to play those ISOs and BDMVs. 
If there were only mkv remuxes just Plex or Emby would solve it.

Yes, for native 4K UHD content on an UHD TV, there is a minimal difference between madVR and other players when it comes to 4K UHD passthrough. Chroma upscaling on displays that most often use a native 4:2:2 chroma resolution is negligible at best. I bet I could still notice a difference in sharpness, but I am not the average user.

DSPlayer has considerable value for those with projectors, anyone who wants to upscale sub 4K UHD resolutions and post-process video content and perhaps those with true HDR display owners that will take advantage of HDR tone mapping for bright specular highlights that is being improved at AVS Forums at the moment.

And don't discredit critical features for hardcore users such as superior 3D LUT support that can have an image-altering impact on the resulting displayed image or projector zoom/anamorphic scaling for scope projector screens. The ability to use 8-bit RGB output with 10-bit content with invisible dithering is also important to many users. There is more there than just HDR passthrough that is valued by most DSPlayer users. These are not the typical plug-and-play users who value simplicity. They want deep customization, flexibility and care about high-end video processing.