I've been using PHP for years and am a believer. It's just as good, if not better in many cases, as other languages used for similar purpose. Especially with the features PHP 7 brings; I particularly like the more robust type hinting. Just gotta write good code!
Cool to see a guitar post on the front page of HN, I suppose it makes sense since many of the programmers I know are also musicians.
I'm a guitar player as well, been playing for about 20 years. Completely agree with all your points, especially that it's a "deep instrument". Many people think there's a progress bar for learning it which maxes out, but that progress bar's max is ever increasing (or it should be if you're doing it right).
Submitted MidiWriterJS about a year and a half ago (https://github.com/grimmdude/MidiWriterJS). I think the majority of the stars and usage it gets came because of that.
One thing I've always found interesting is that technically, by definition, we're currently in an ice age:
"By this definition, we are in an interglacial period—the Holocene—of the ice
age that began 2.6 million years ago at the start of the Pleistocene epoch,
because the Greenland, Arctic, and Antarctic ice sheets still exist."