Agreed! Our Salesforce team is constantly making modifications to improve and consolidate fields. As those fields are removed, we have to make assumptions around what we 'believe' will be impacted and hope we catch everything. Being able to select a field and then see all the places in Gainsight that it is used would be a huge win. I would expand this to include standard objects, reports, and rules engine.
I totally agree with the capabilities this feature brings in to the table along with a unified view of all the places a field is being used. But for now, we can know the usage of a field in custom rules using Config snapshot.