@Abosede-Christiana0,
Lodgify probably wants to make you use the API channel manager because this enables them to track your bookings across all channels. iCal synching only shares date blocking information but doesn't specify the reason, e.g., blocked by owner or a reservation.
Please note that if you currently have the service fee payment as split pay (hosts - 3% and guests pay 14.2%+) when you connect any exterior software, e.g., your Lodgify site, to your Airbnb account that the service fee payment format will default to host pays 15% of the total rental rate and fees. Also, if you have the starter version, you must pay Lodgify a 1.9% commission on every booking even if it's made on Airbnb or any other channel.