Another downside is too many of these phone activation systems ONLY deal with cell phones with text messaging. I know every phone in the US that can be used on the networks has text available, but some of us flat refuse to pay $30, $50, or more for something we might use for, at most, an hour a month. When you use burner phones, every one of those text messages adds up to the cost of doing business.
Phones are for the 90s. Please leave them there. Let's get universal Wi-Fi and a device and we can leave these shitty telecom companies behind. (I know... they'll be running the network connections just like they do now.)