The only point IMHO to built in battery, is if it very convenient to recharge, which is not the case. I have an HHKB which uses 2 AAA, with rechargeable Li batt

The only point IMHO to built in battery, is if it very convenient to recharge, which is not the case. I have an HHKB which uses 2 AAA, with rechargeable Li batteries which I can reload with usb, while still using the keyboard with cable (once every 6 months or so)