Bollywood has always been about "The Experience"—the colors, the grand sets, and the larger-than-life musical numbers. For decades, this was restricted to single-screen theaters and later, multiplexes.
Most modern OTT apps now support in high quality. While they usually use MP4 or proprietary formats, the visual fidelity rivals any MKV.
MKV files are widely used for Bollywood movies because of their versatility: