Short version: you can do more with wirelesstags than measure your humidor's temp/humidity
Long version: I guess it depends on what your purpose is for purchasing. For me, it came down to this. I needed something to accurately give me readings of temp and humidity, without having to check 3 different places where my cigars are stored. I could have gone with an Ambient Weather WS-10, spent $50 and have a "home unit" sitting out (tacky) or in a drawer somewhere at home; but that would only allow me to know what the temp and humidity were when I checked it and not the other 99% of the time. This matters when setting up an active temp humidor like a wineador or have thousands of dollars invested in cigars and wouldn't mind a little more assurance that you're keeping them stored correctly. Wirelesstag was $60 more and allows me to do much more. On the cigar front, when coupled with Wemo plugs, it can replace an electronic temperature controller, runs fans when humidity is higher in one area than another, or turn on an LED light when you open your humidor. If you like to tinker or enjoy electronics or enjoy customization, this is for you.
Additionally, wireless tags can be used for many other things I planned on doing anyway. For example, I'm about to buy another tag that I'll use to detect movement of the garage door that will send a signal to a Wemo plug located inside the home to turn on a lamp anytime between the hours of 7pm and 7am upon my acknowledgement for when I get home late from work. I'll add more when my son starts coming home after school to know when he gets home and to use as a makeshift security system to turn on a wireless camera if there is motion detected at the front door.
All that said, it may not be for you.