Well, MIDI data itself is still in heavy use in music production, both to interconnect hardware, and within software itself. It's the standard way to represent notes, timing, events, etc. within music-making software (DAWs).

Actual MIDI files themselves? Mostly just used as a file format to share musical/rhythmic motifs or export between music apps, not as an end product in itself.

Midi's are also used in streetorgans. (Which sounds way too 'computerized' in my opinion. Example[1])

[1] https://youtu.be/U9dxscRz5ek

I prefer this one (no MIDI in action to see, though): https://www.youtube.com/watch?v=fnb7EqfykF4

Ha! Nice! (After all the system used is a precursor of midi.)

What are "MIDIs"? MIDI is a singular mass noun, like USB or Firewire.

The MIDI protocol is still dominant in the professional field for which it was designed: controlling electronic musical instruments.

By "MIDIs" I presume you don't mean MIDI but rather so-called "MIDI Files" (SMF) and the "General MIDI" (GM) spec. This junk was originally designed for consumer-level products like Casio keyboards. General MIDI eventually devolved into the ghetto of cell phone ringtones and other trash. But don't confuse this with MIDI proper, which is a long-lived professional specification controlling often very sophisticated (and costly) devices.

Dave Smith -- largely regarded as the founder of MIDI, lamented this recently too. See 00:25 here: https://www.youtube.com/watch?v=RnemYKi8Tb4