Unlike most languages it's inherently two dimensional because music includes both horizontal (time, rhythm) and vertical pitches (chords/colours, harmony) information.
And - especially important - melody is an element that needs both.
You can't represent the same information with text without losing a lot of important content, which is why toys like Sonic Pi are more limited than they seem.
You can kinda sorta represent the same information on a piano roll, but it's not any easier to read than dots - in some ways harder, because you're not going to see the relationship between a bass line and chords as clearly.
Is it a good programming language? It's quite dense, but not denser than some code idioms. The 2D element is unique, and hard to represent in other ways.
The learning curve is steep, but it's probably as good as it can be given the requirements and constraints.
I know neither is about music notation per se (but about fixing the piano), but it is analogous: Music notation has exactly the same problem as the piano -> it defaults to C, which makes everything else relative to C and overly complicated.
For the record, I don't think this means we should switch to a new system, but it is usefull to recognize that it is suboptimal, if only to be able to accept it and continue (because nobody is going to translate everything to some new notation)