Well, even if you left the pickup dangling and not able to reach bottom of the pan, technically it would still cool better. It would pick up what it could, it would cycle through the engine, when it comes back hot into the sump, the reservoir of oil would be greater, and cooler than cycled oil. If you add hot oil to a little bit of cool oil, the temperature would be greater than adding hot oil to a larger amount of cooler oil.
Not reach it all the time makes it less efficient, but it all is going to get cycled back and combine and then repeated.