maybe they left the "A" because the use of that letter in photographic equipments is trademarked by Sony. So, they chose the next letter b.
Anyway, this thing is small. But, like someone said here, it's not small enough to be pocketed, nor is big enough to be held well. But, this thing is clearly aimed to the first time dslr buyers. And i'm sure, most would fall for the size when compared to other things.