Of course, you are using the major channels such as Expedia and Booking.com. But how many reservations are you missing out on by not being on channels from other countries or activity specific channels such as Ski.com?
In the past the primary reason to not be on many different OTAs was that you had to manage them. No one wants to be on 10 or even 50 channels and manage inventory and rate changes. It is even difficult to just manage a couple of the major channels. In the past the old 80/20 rule held true. Eighty percent of your OTA bookings come from twenty percent (or less) of your channels. But that means that your are missing out on 20% of OTA bookings simply because you cannot manage additional channels.
If you manage your inventory through the OpenHotel Channel Management system, you update your rates and all channels are updated. The channels pull inventory from the OpenHotel PMS. The reasons for not increasing to many different channels suddenly goes way.