According to a recent study by Cornell University on the so-called billboard effect, almost 75% of the traffic that booked on a hotel brand website visited an OTA prior to making the purchase, and three to nine of those bookings, were directly influenced by the OTA listing. The take away: a listing on the OTAs, will generate more bookings (on your site and the OTA).
Furthermore, if you have high quality, large photos, videos and/or 360-degree tours on your website and on the third party sites you will generate more booking, period.