Reportedly, BME is also useful for charging from a PC. I don't know if it's true, as I can easily access mass-storage mode with bme disabled, and then, modified version of charging script/module (that would draw no more than 500 mA from USB port) should be OK.

BME is also responsible for low battery warnings and shutting device down gently on low power (via rather complicated guess-working of "when voltage down spikes could piss of cellular modem", instead of some simple voltage threshold), but this could be re-written in kernel module.

/Estel