It says "full anonymity" but only mentions an ID. So an ISP can tell I'm using it and what time as opposed to Tor or something which obfuscates the network of w

It says "full anonymity" but only mentions an ID. So an ISP can tell I'm using it and what time as opposed to Tor or something which obfuscates the network of whatever messenger? Surely on digital networks we've come to a better definition of "full anonymity". Also, I assume I have to trust the company, which is sadly normal in these cases. I can't run a server on my own?