Trust me there are differences

EULA - End User License Agreement, is an agreement between your self and the company and thus being a contract between you and blizzard.
In a court of law even a verbal agreement can be binding when two parties make a consensual agreement.

By creating an account you basicly sign the agreement and for the continuation of the service when patchs and updates come out that you have to accept to the agreement, you have the option at every patch to either accept the renewal of the agreement or the cancel and decline the agreement.

Its the fundamental law backing contacts agreements, blizzard give you the option to terminate the agreement and not carry on.

Same fundamentals on any agreement, there maybe sections which could be unlawful but if they were someone would of Sued and won by now, and AFAIK the EULA doesnt break any rules because at the end of the day the EULA words it as you RENT/LEASE your account and have the power to terminate the account at any point with no reason.
The power lies with them.