Customer would like to have a scanner for each of geographical region.

For instances: imagine that you are geo-distribuited and have replicas of your registry across three regions. When someone from a geo region tries to push new code you want stackrox to scan using the closest scanner to the registry.

At the moment, since you only support either one scanner, or multiple scanners from different providers but all of them are run, you cannot optimize this. 
Therefore, having the console instrument what scanner is utilised will help scale the solution. 

See also https://github.com/stackrox/stackrox/issues/5790 

Also:  

We have a use case where we use a dedicated link to offices branches to make sure we interconnect registries. That link does not have a huge capacity and we were thinking of having a Throttling feature to avoid resource consumption in pulling images from central to be scanned.