I don't know what rationale Apple is using to decide they should be discontinued. Perhaps they ordered some large quantity years ago and finally have run out? It's such a useful little accessory for those of us with really good wired headphones.
I use mine with HiFiMan Edition XS open-backs and a separate DAC. The combo sounds so much better than any of my wireless headphones. Bonus: I don't ever have to worry about the batteries giving up the ghost as they all eventually do, forcing me to toss out expensive bluetooth headphones. I also have a great pair of closed-back B&O's more than a decade old I sometimes use. There's no wireless ones that will last that long.
That little discontinued dongle saves me a lot of money, and allows notably better sound too.
