Adding a feature because ChatGPT incorrectly thinks it exists

Here's the thing: I don't think ChatGPT per se was the impetus to develop this new feature. The impetus was learning that your customers desire it. ChatGPT is operating as the kind of "market research" tool here, albeit it in a really unusual, inverted way. That said, if someone could develop a market research tool that worked this way, i.e. users went to it instead of you have to use it to go to users, I can see it making quite a packet.

They only want ASCII tablature parsing because that's what ChatGPT produces. If ChatGPT produced standard music notation, users would not care about ASCII tablature. ChatGPT has created this "market".

ASCII tabulature was not invented by ChatGPT, it is decades old thing. It is easier to write with basic computer capabilities, and also read for ChatGPT (and humans with no formal music education), so it is probably even more prominent in the Internet than "standard graphical notation". So it quite expected that LLMs have learned a lot of that.