That would be good if it wasn't for the fact that quite a few home routers have a screwed up SNMP implementation.

If you queried the transfer counters on older Speedtouch routers, you'd get a weird value back. It would increment if you downloaded/uploaded but the actual value it increased by would have little to no relation to the amount you actually transferred. I worked around it by basically scraping the data out of the telnet CLI.

I've had similar issues with Netgear routers as well but they were usually unreliable in other ways as well which meant them getting binned.

All of this effort is to get line stats into MRTG.