Depends on where you will be using it. Here, folks even air condition tents, because we can have daily highs over 100 F for 2-3 months without a break, and when it gets that hot it is because we are stuck in a mass of humid Gulf air, so temperatures seldom drop below the dew point at night, maybe 10-15 F below daytime. We don't sell many popups down here because of this. What the popup is about is a tent-like camping experience, and closing up the tent to blow in cold air negates that experience.
But I grew up in Michigan, we didn't air condition our houses, cars, travel trailers, or tents (before the 1960s). We went camping all summer, "hot" usually meant just over 80 F, and it usually cooled 15-20 degrees at night. Doing without A/C while camping, however, meant camping in the shade, or staying outdoors most of the day. Park your RV (or set up your tent) in the open sun, it can easily heat up to 20-30 F above outdoor temperatures. Of course a popup, you just leave it open.