It matters because it is where profitability becomes visible. Time recorded against the right contract is what tells you which clients are worth serving and which agreements are being consumed faster than they are priced for. Without it, the numbers exist only as an impression.
The common failure is treating it as a helpdesk with invoicing attached. If technicians record time loosely, or tickets are closed without being categorised, the reports produce confident numbers built on nothing — and decisions about pricing and staffing get made from them.