Why do release groups use MKV? Because it supports virtually everything. You can have a 4K HDR10+ video track, a lossless DTS-HD Master Audio track, a commentary track, and 30 different subtitle languages all in one file. MP4 cannot handle this level of complexity natively.
If you encountered this while searching for a specific movie or software, I recommend checking official platforms like Netflix, Amazon Prime, Disney+, or legal download stores instead. mkvcenema repack
Smaller files are much quicker to download, especially on slower internet connections. Why do release groups use MKV