This could open up a pro and con discussion of Open Source software. …
Except that MuseScore really isn't anymore and neither is Audacity, now owned by the same company. Oh, you can make pull requests on Github but a development team oversees everything. Frankly, I think it's a good thing.
As to that "Always free" part or, in their words,
the limited "free" account. Basic functionality, yes but you want the "pro features", that's $49 a year (which I pay) or $6.99 a month.
So why do I pay? Sometimes, I find scores I can use with my ensembles. They are always in terrible shape but editing them into something I can use requires Pro. Normally, I export them as MusicXML and open in Finale, Dorico or Overture. If I don't care how they look and only want to play them with decent VIs, I open them in Notion 6 where assigning VIs couldn't be simpler. MuseScore doesn't support VSTs yet.
but then I use keystrokes for much of what I do.
Nice if you have two working hands—not everyone is so equipped. Annoying to have to use a hand and a mouse to do many tasks.
Finale, Dorico, Notion, Encore and Overture require one hand
or a mouse to do everything.