CPQ by CallidusCloud is not native to Salesforce or any other CRM system, which brings various benefits. Computation power enables the CPQ engine to price while configuring, instead of waiting on the user to initiate pricing action. CRM systems are data intensive, not computation intensive.
In addition, CPQ sets no limits on products, configurations, or rules. You have the flexibility to customize and enhance, unconstrained by CRM code. And you can make pricing or product catalog changes for your CPQ yourself, without relying on your current CRM administrator.