It's 298 bytes per page request given the example he gives (your token can be smaller or larger depending on the data in it).

It's 24 MB of bandwidth to the -server-. Your server -better- be behind a decent broadband connection, or what are you even doing?

1/3rd a kilobyte per page request to the -client-. 1/3rd a kb is a blink of an eye even on modern dialup.