Sorry, but password complexity matters a great deal. When a website's passwords get hacked, they're going to compare hashes and find all the easiest ones first (password, hunter2, 123456, etc). If yours is 15 characters of random letters, numbers, etc, yours will not get cracked first. Now, if someone like the NSA is targeting YOU, then it doesn't matter how complex it is; it will get cracked. But in a list of 5,000,000 passwords, having a complex password can help make sure yours is not one of those cracked.
This is my exact point. You are right if and only if the provider didn't bother to use an effective salt, which renders rainbow tables pointless. Why isn't that part of the meter? "Your password is stored in a hash of type XXX that is ### bits long, hashed for ### rounds, and salted with ### bits during each round." would tell the user all they need to know about how well their password is going to be protected, and they can make a more informed decision.