I know it may not seem like it, relative to the cost of the hotel without it, but the IHG Rewards version is simply a slightly discounted way of buying points, nothing more. And thus works the same whether it seems to be a good value or not, if you want to use less points.

It is a good value if the points alone are a good value, it is a bad value if the points alone are a bad value, but it's the same cash component for a certain number of reduced points every single time, so the value of moving between points only and points + cash in the IHG Rewards program never changes.

(As opposed to the HH program, where it's not as simple as that.)