My old pool didn't have an overflow, but, when it would rain and looked like we were going to have several days after that with no rain, I would regularly let it stay higher than normal, knowing that I would have quite a bit of evaporation without rain. Usually I ended up having to pump it down in the end.
Are you planning an autofill? If not, I could see that working as well, if you are going to be out of town, you may want to put a bit more water in before leaving to make sure it doesn't get too low while you are away. We are doing an overflow now, but, no autofill. Honestly, I just felt like it was a waste since I will generally have eyes on my pool every day and have a hose near by. Of course, here in Central FL, we get a ton of rain, so, it's rare that water needs to be added.