Now that tethering has become essentially ubiquitous, there is little need to have a cellular radio in every device. I just went through the same calculus with an iPad... my original had cellular data, which I cancelled as soon as I could just tether it to my phone. I agonized over the decision when replacing it, but ultimately grabbed a wifi-only iPad Air 2. Any time I have my iPad, I'll have my phone with me too. Chances are the same is true for you and your Kindle.