Can anyone explain to me, what's cool on web midi? I me for me it's totally useless.
I have a lot of sequencer, synth and midi help plugins in the DAW ... what does a JS interface to the web offers other than the next 100th "I just wrote a little useless javascript music script"-show HN posts?
For me it doesn't solve any problem or satisfy any need. It's just another other thing almost nobody uses in the browser.
One use case is education, where a web app is often easiest to build and deploy.
There are lots of rooms equipped with computer, notation software and keyboard in music institutions, where webmidi seems like a great way to develop some quickie music theory/education apps.
The web is not anywhere near parity for music and audio production yet, but its proponents see webmidi as one necessary step to that direction.
(I would personally not use current webaudio/webmidi software, but have successfully deployed a lot of it for education!)
I would argue it also lowers the barrier to entry for experimenting with new techniques for generating/processing audio. For example, you could pretty quickly create a page that has touch controls for adjusting parameters, uses a neural network for generating MIDI data, and then outputs that MIDI to a VST running on your computer.