[shakkhar]

Yes but that is just the baseline. You want HEVC / VP9 for browsers which can play that, you want 5.1 audio for home theaters, you want adaptive streaming when the support is available, and so on. You don't want just the minimum for _all_ of your clients. You want some code that tailors the experience based on client capability. That's what the JS player handles.

[vim_wannabe]

Adaptive streaming sure, but can you not handle the different audio combinations using source-tags? And HEVC/VP9 with h264 fallback I would imagine is the primary use case they (WHATWG?) were thinking of supporting when creating the source tag.

[prebrov]

Technically you could have a single URL that returns any manifest based on user-agent or whatever player info is available in the GET request.

But yeah, JS players make life a whole lot easier by providing a single API for customisation, handling media source extensions and a bunch of other stuff.