If you do not give this permission it is most likely that ADDM will be able to get information from the host using WMI but won't be able to get information using remquery which is used when things cannot be obtained via WMI.
It also means that patterns will not be able to run commands locally on the host to obtain the data they need to obtain.
So in summary, these credentials will most likely result in ADDM not being able to obtain the all the information it could and therefore the level of detail provided by ADDM will be less.
The best way to see how much would be missing would be to scan a few hosts (different Microsoft Windows versions) first using a credential giving more access, reviewing what was discovered, then deleting those hosts and re-scanning using a credential with a lower level of access and comparing the results with the original.
That will give you an idea of the tradeoff involved with respect to level of information obtained if using stricter access policy.