Pricing & Availability (P&A) management ensures the guests are only able to order menu items that are available, for the correct price configured by you.
For menu P&A, the source of truth is either the POS or the Digital Operations Portal (DOP) depending on the integration in your brand/market. While a part of the configuration (mainly PLU definition) is still managed in Sanity via the Vendor Configs, the actual values for the PLUs either come from the POS or the DOP.