I don't know how it generates the instrumental part, but it's not an LLM.
Discussion
Fair enough, I tend to say LLM as it’s not a form of intelligence, it’s just compiling everyone else’s work.
It doesn't matter what you call it or what you think about it if it helps you do a task faster or with less effort.
I use a couple of machine learning tools marketed as AI for that reason but that's different to making music by typing a handful of commands.
So what do think about voice conversion? It won't stop till der Fuehrer covers every song in existence.