You think booking revenue at a later date restricts them from spending the cash they receive now? It helps them because they receive cash that can be physically spent for whatever they need. FASB guidelines just prevents them from matching those expenses to revenue from a tax perspective. If I receive $250,000 in gift card sales in 2020 but all $250,000 get redeemed in 2021, then your revenue in 2020 should not reflect this $250k, but instead be reflected in 2021. All else equal, in the event the restaurant owner took the convenient and simple path of recognizing the expenses in 2020, it would just mean their tax bill in 2021 would be much higher because their net revenue (sales - COGs) would be high as a result of the $250k in revenue being realized.

Source: I used to own a restaurant.