Any traffic should be limited by that queue.
That is not the case: it depends... in case of simple queue on your configuration. If the traffic is switched / bridged and "use-ip-frewall" is not set, it will NOT pass through simple queue.
So you'll need to either set that or change queues used.
On queue manual page (linked earlier) you'll notice there are 2 types of queues: simple & tree. The last one is linked to interface and applies at different point: -> "Interface HTB" just before physical transmission.