Well if you have WiFi calling abilities through your router then you wouldn't necessarily need a cellspot. And LTE cellspot creates LTE signal from your ISP. That devices for people who have no signal at all. The LTE booster of course takes the outside signal and puts it inside the house at the same level. But does not require your ISP. A WiFi cellspot which is no longer available but acts just like a router but has voice prioritization built into it is basically just a router that allows prioritization to voice. Again if you don't have any signal you would want to sell spot if you have weak signal on the inside but strong on the outside you may need a booster otherwise you just use Wifi calling and texting on your own router. Voice power to station just means that the router will prioritize wifi calling over internet browser gaming data use.