said by mjr:If comcast is charging anything substantial for a battery to backup the CM, I would just suggest people get a cheap UPS and backup whatever they want... But that's another topic.
COMCAST charges $35.00 plus taxes and a $5.95 shipping fee for up to eight hours in the event of an electrical outage.
NAS is a double meaning as an acronym. I am not sure if you are talking about a battery, or a backup storage for your computer.
In any case the only real reason I can see RCN using two devices instead of one is that it is easier to charge the $5 fee twice.
But even if they charge $10 for the "residential gateway" the customer would be paying the same monthly fee, but they would have wireless for a few hours.
Many electrical outages only last a few hours anyway. It would greatly increase safety.