One think with the battery warning is that if you have a BT headset hanging around your neck, the beep goes to the headset. OK if you have the earbuds in the ears, but many times you may decide to have the earbuds in the ears just during phone calls.

Another thing with the battery warning is that it starts to warn first when the batteries are very depleted. I have had phone calls where the phone died within three minutes of the first warning.

The battery warning signal really should have special handling in the phone, allowing me to know about the problem even without the earbuds in the ears. And a good choice how to know about the problem while I'm in a meeting - the availability of a phone may actually be several times more important than the meeting and motivate a short break to get a charger.