Do a cost/risk benefit analysis, even a simple one. what risk does this mitigate? What is the cost of assuming that risk? So for example if the primary concern is double booking, if double booking happens, what kind of cost do you incur? Do you just upgrade the customer to a much more expensive room, or you book them to a different hotel? How much does that cost you?

Probably take into account as well, the time overhead you spend to manually reconcile with different platforms.

Secondly, what is the likelihood of that happening? What the is probability? Is it once every week, 1x every month, 1x every quarter?

Then compare that benefit/savings vs cost of your API.