I can see limiting highly-restrictive speed limits, as there could be a broader public interest in having traffic moving. Like, when traffic is moving from point A to B to C, B may be on the only route from A to C and not care how long it requires to get from A to C.

But how does limiting traffic cameras make sense? I mean, either you have a speed limit or you don't. I can't see a good argument for limiting enforceability of speed limits.