You're obviously an outlier and therefore not the target customer. Most people don't even use that much on a home internet connection. Where this pricing shine is for folks that don't use lots of data. To top it off, the data doesn't expire/reset. I personally use less than 1GB per month, but on a regular phone plan, the best price you can get is $5/month for 1GB. With silent.link I can outright buy 12GB for the whole year for $14 instead of $60 if I'd stick with a phone plan.
Discussion
I wouldn't call myself an outlier since vastly more people use normal phone plans than use anonymous phone services. If anything, people who opt to use these services would be the outliers in this context.
In terms of my specific data use, I'm definitely an outlier because, as you mentioned, most people don't use as much data as I do. But that's exactly why I was careful to buy a plan that met my particular needs.
If you read the rest of my comments, you'll see that I brought it up because I'm not informed about these services, and the price was the first thing that caught my eye given the vast difference between my Verizon unlimited plan and this by-the-GB plan.
This would obviously not be the right service for me given my data needs, but after talking with some kind and patient people, I understand that every use case is different, and call for different solutions.