I have resisted the term, because whatever someone prefers in the character of their system is going to be the one which draws them into the music, no?
If that’s true -- and I cannot see how that can be disputed -- then every system which someone likes is "musical."
What if someone’s ear does not care about the kind of distortion @atmasphere identifies with musicality? Would we say their use of the term "musical" is incorrect? This would be tantamount to saying that "good food is spicy food" and then for anyone who demurs, they like "not-good" food. Would we say that some people like "not-musical" amplifiers?
That said, I do see that some here are trying to help associate the word "musical" with its most frequently used associations -- lexicography, if you will. It's "rhythm and pace" or "2nd and 3rd order harmonics," etc. Maybe that's useful. I'd still expect a lot of people to just use the word to mean other things, and not really be incorrect in their usage. This makes the word of suspect usefulness.