This is targeted at low-income consumers who can't afford anything but the lowest-rate plan. Since they will also be the most likely to value an extra $5/month,

This is targeted at low-income consumers who can't afford anything but the lowest-rate plan. Since they will also be the most likely to value an extra $5/month, this is a way for Comcast to milk them for extra money each month when they inevitably go over the 5GB limit. It's a scam.