Agreed. The whole idea for using a simple, stripped-down boot disk is to create the most stable environment possible. That said... a battery backup would be nice... if the power blinks while you're flashing, odds are you're gonna be in a world of hurt.
On a separate, but semi-related note... I once (many, many years ago) flashed a motherboad with the wrong brand of BIOS... whoops... thankfully there are safeguards in place to prevent that now.