Right now, most activity is saved under the contact. If that person changes, notes, calls, and appointments can be lost. Opportunities should hold all key info (notes, tasks, calls, and events) with contacts linked as participants. That way, every opportunity keeps its records even if the main contact changes.
We use GHL for our real estate business, where one owner may have several properties. Each property is its own opportunity, but because most workflow triggers are tied to the contact, it’s difficult to take full advantage of platform considering the contact ends up driving everything.