New-NetVirtualizationLookupRecord flexibity

I just have a quick question. What is the rationale behind the call of New-NetVirtualizationLookupRecord? it seems that it needs to be done per VM and per NIC ( as it requires MAC address). 
It will be a challenge if we have a large number of VMs to deploy as we need to collect each MAc address, each CA to call New-NetVirtualizationLookupRecord 

Thanks for your explanation!