DAE regret buying a $180 proofing box until they moved to a cold apartment

I swore my dough was just weak for a long time and kept blaming the flour. Then I moved into a place in Minneapolis where the kitchen sits at 63 degrees all winter and my bulk ferment went from 4 hours to 7 with zero change in recipe. Out of spite I spent $180 on a folding proofing box with a little heater and a dial, and honestly it made me feel like a sucker for about two bakes. Then I did the same 75% hydration dough side by side, one in the box at 78 degrees and one on the counter, and the box one doubled in 3 hours flat while the counter one was still sluggish at hour 5. The crumb on the box loaf was open and even, and the other one had that tight gummy spot near the bottom I'd been fighting for months. I still think $180 is steep for what is basically a warm plastic tub, so I want to know if the cooler with a mug of hot water trick gets you the same result before I tell my sister to buy one. Has anyone actually measured dough temp in a DIY setup and compared it to a real proofing box?