What is meant exactly by the description 'more musical'?

The word "musical" as used by audio buffs is a subjective adjective generally understood to mean "x,y, or z sounds good to me" See "organic."

Antonym: "unmusical.

More musical  =  More money

To me, the test is: do you hear more of the emotion in the recording performance?

In the end, that’s what it’s all about.

more emotion = more engaging = less listener fatigue. 

Music is processed by the limbic system of the brain. But if there is something wrong (like distortion) the processing is unconsciously moved to the cerebral cortex. There is a tipping point for this. When this occurs the presentation loses some of its emotional impact, the toe tapping, that sort of thing. So to me, "musical" has always been about keeping that engaging quality.

Very well said...

This reveal why pure subjective characterisation of what is "musical" may become meaningless pleonasm if we do not identify also what are the acoustics and psycho-acoustics conditions that may impede or increase the emotional and gesturing body impact of the musician as well as of the listener ... The fingers of the violonist moves and our body parts moves with him ...

In a word, we may become analytic , critical, and distant from the music , the moment the sound loose for us and for our specific ears/brain characteristics the refined balance, what you called the tipping point , between all acoustic factors implied , some distortion or some harmonics, or some level of noise, or some excess of reflection or excess of absorption in a room or a bad timing between direct and reflected waves etc ...

For sure there is always a subjective relative acquired taste in the definition of "musical" ; for example for me nothing is less musical than a rock concert at high decibels levels...For others it will be an epiphany of musical collective trance ... But if music can participate to collective trance i dont think that music as contemplation and healing is associated with the collective hysteria of a crowd at high decibels levels ...Something work no more here for my limbic musical brain and my cortex want my legs to go near the silence ....For others it is the opposite, their limbic system is happy with a collective noisy crowd...

Acoustics define music as meaningful sound first and last , and it goes far more deep than our taste for a specific set of frequencies and decibels ...

For example all the details of information communicated through  the meaningful sound of a sentence  spoken and articulated and rythimically throw in a certain way ...this set of information could fill a book  about a character deciphered by an attentive experienced listener or by our unconscious limbic system  while our cortex sleep awake ...😊

Music is processed by the limbic system of the brain. But if there is something wrong (like distortion) the processing is unconsciously moved to the cerebral cortex.