Would be valuable for us from a sales perspective, if we know the parent / subsidiary company relationships, it would help us get our foot in the door with the other related companies. For example, if we have a strong relationship with a parent company, it would nice to be able to quickly see their subsidiaries (if any) and try to sell our services across those companies as well. Also works the other way, strong relationship w/ a subsidiary company -> sell our way up to the parent company.
Let me know if i can provide additional context