SE just fail at marketing.
To the consumer, it sounds way nicer to say : $9.99 + $3 per extra character rather than : $6.99 without any character + add $3 per character.
Following the billing announcement today, a lot of medias published the news, and feedbacks from non XI/XIV players were almost always "wow, charging $3 for a character, this is retarded". While if it was advertised as an extra service (since after all you can do everything with one char), there would less negative feedback.
And I believe that SE should even mention on the billing page that one character can plays all classes.
A future customer coming out from any MMO out there, willing to try XIV, checking the fees page and seeing "$3 per character" may just run away because of that, without even bothering asking/looking for more information.