I'm not sure what you mean by bus bandwidth - ? Even if I did, I don't know the answer to your question

The CPU looks decent for this sort of thing, quad-core ARM A7 with 512 or 1GB memory. Wi-Fi is only 802.11n. I suppose it depends on what you want to do and/or expect for $29

To be clear this is sort of like using a Raspberry PI for audio, there's a (very*) good chance you will need to tinker with it on the command line, although the web GUI looks useful.
(*) Note that the device is new and the OpenWRT port is done by the hardware manufacturer, so it could have "issues." If you were after something that is supported by OpenWRT have a look at this list -
https://openwrt.org/toh/start