I lobbied hard for this over the default Asterisk knockoff-Enya hold music last time it came up, at least for programmers who only over put people on hold if we have no intention of actually talking to them, but I was overruled every time.
Yes. Well, we're trying not to make our customers feel hated. The worst part about most IP-based hold music is it fucking starts at the beginning every time you move in the queue. Apple was the worst for this, especially as their call centers were all wired together using coat hangers and baling wire. Crackle crackle fizz fizz distorted guitar fizz crackle "hi, I'm representing the world's largest tech company can you hear me sir?"
From experience, making a large phone system that doesn't suck is a pain in the ass and not enough of a priority to the powers that be, so you can either have a humorless phone system that makes your customers feel hated or a humorous phone system that makes your customers feel hated. I'll grant that you probably have more room to approach not-infuriating than most of us.