I've used their products for years with cigars. When storing several hundred dollars worth of tobacco for months, you definitely use a product you can trust. Florist foam and propylene glycol....what a mess. The packs are two way humidity controls. They remove or add humidity to the air. Within reason. If someone says differently they either haven't tried them or are just not using them correctly. I will say in my experience they raise and hold much better than lowering the rh%.
I did pick up the 62% packets to help me feel confident that I had gotten everything to the right point. I have a couple calibrated hygrometers that read spot on in mason jars with the packs.
Disclaimer: I used the boveda calibration bags to set the hygrometers. So, if it's off, I'm impressed they had both packs off the same amount. 75% cal and 62% jarred.
I prefer the 69% packets for sealed "humidors" and definitely the 72% on wood/traditional humidors as they all leak just a bit. Never had a large enough one for a powered humidifier. Dreams of a walk-in.......