CPQ, billing, contracts, and renewals are implemented as part of your revenue engine, so nothing about what was sold, how it's billed, or when it renews lives in three different places.
Most companies run revenue across disconnected tools: a CRM for the deal, a document for the quote, a spreadsheet for the contract terms, and separate software for billing. Every handoff between them is a chance for the numbers to drift apart.
Revenue Hub, implemented properly, puts the deal, the quote, the contract, and the invoice on one connected record. Sales, finance, and customer success work from the same revenue data, instead of reconciling three versions of it.