Short answer
HubSpot's KB: payment properties work with HubSpot payments or Stripe. They're HubSpot-defined and can't be managed in property settings. Using them in workflows and custom reports needs Professional or Enterprise. One example: Total Remaining Amount for fixed-payment subscriptions.
1. In HubSpot
The relevant screen in my demo portal.
2. Worth knowing
Report on these instead of copying values into custom properties.
3. Related
Deal revenue properties and payouts.