They already have that data through historical patterns. Back when I worked in restaurants before the days data analytics, we would keep track of the number of covers we would do and then refer to them the next year to determine staffing for the same time during the current.I don’t think it will. It’s free data collection for Disney, formality or not. It lets them know what park you plan on visiting. It’s definitely not going away unless some sort of fastpass returns.
Having to make reservations just to go to a particular park is one less reason for to return to visiting WDW