I can't speak for others ... but I nearly bought one of those months back when I was first starting. Fortunately I researched and through AA I found it's really not necessary. I wouldn't want to buy anything to reduce ammonia ... that's what the BB and plants are for. Let them do what nature intends for them to do ... consume ammo.
Those ammonia reducing pads and chemicals is just another way for them to get $$$$ off customers. IMO if a tank is properly cycled / established ... you should only have to worry about nitrates building up. In those cases, plants and PWC's come to the rescue. The only thing I'd buy to lock ammonia is seachem prime.