Nothing will happen. Theoretical seating is a function of Amadeus Altea. This is the underlying system with FLY being the front end. The article isn’t totally correct as BA didn’t have Altea before FLY, the 2 came together. Before 2016, BA used PRS.

BA switched from FLY to Altea at departure gates pre-Covid. FLY remained for check-in with periods where BA at LHR used Altea for certain periods, including during disruption. This helped identify areas that BA worked with Amadeus to develop therefore enabling the full switch to Altea.

Overall, there was nothing wrong with FLY. Issue was the architecture behind it and how the decision-makers at the time choose to connect to Amadeus. In many ways, FLY was easier to read and use, with fewer clicks to complete some transactions. In other ways Altea was better. Hopefully the upgraded Altea takes the best of both.