My numbers are from measuring round trip latency through headphones and phone's built in mic and then basically guessing which part is input and which part output latency (they're both small). 200ms is certainly in line with most Bluetooth headphones. I'm not sure what the guy is doing differently from the app I'm working on, but for us AirPods are clearly the lowest latency choice.
EDIT: Ignore what I wrote below and see the update. I'm getting similar latency numbers.
Generally, the guy is getting so massive latencies that I suspect he's doing something wrong. The app I'm working on has MIDI to wired audio latency around 10ms when audio buffer size is dropped to 128 samples, so 70ms sounds really excessive. Touchscreen is both slow and the timing is all over the place (try playing drums in GarageBand to see) so it might explain some of it.
Ok, I'll take back what I wrote above. I tried the measurement again and got 197ms round trip for the same 2nd gen AirPods and iPad Mini4 running current iOS. It's not the worst, but certainly not better than most of Bluetooth headphones. I'm not sure why I got the low number before and whether it was a measurement error or changed in a software update.
From what I am reading, the best of the Bluetooth headphones are claiming say 120 ms, and some have as high as 300 ms.
I just hope manufacturers keep making wired ones with active noise cancellation (ANC). Already it seems ANC is seen less often for wired ones than for the wireless ones.
My guess is that since ANC already needs DSP and small headphone amp, it doesn't cost much to add a Bluetooth receiver. Removing the cable input socket and ADC could even recover some of the cost. On the other hand, it seems that there's limited market for wired headphones right now.
https://semiserious.blog/airpods-pro
Is the latency under A2DP mode specified somewhere?