I would think having this on their Facebook page, website or hanging in their booth at an art fair is meant is to either reinforce the attitude or create it and I would not find it out of place at all. Handmade pottery is a niche market sold mostly to those that appreciate it for what it is and the backstory of the artist is certainly part of what it is.
Doing a blog is also a way to accentuate that the pottery is made by a real person. I think one of the reasons that good potters seemed to have done fine through the down turn is that potters enjoy a nice slice of the art/crafts market as many of their buyers might have turned it down a notch on other types of artwork but kept buying pottery because its both decorative and functional. It's/We're special ;-)
Look if I sold pizzas It would be because I was passionate about pizza and they would be made with nothing but the best and most expensive ingredients and my pitch would need to essentially be "come buy a really expensive pizza from me". While I agree with Carl that a perfectly fine mug can be had at target for a fraction of what most potters charge for a mug, I disagree that they are not better, I think they are better in almost every way. However they do not hold coffee any better than a machined mug and if your potential customer does not know the sentiment above then hey it might sway them your way by getting them to read it and maybe open their wallet. Not everyone at the fair, on the Facebook page or website has come over to our side so we have to entice/encourage them to stay and buy something.
If this had been called delusional in another area of the forum I might not have responded but Phill posted it in business so I had to challenge his view and hopefully get him to re-think his opposition to using such blurps. In order to sell art I think it is so important that modesty and the need to sound a certain way needs to be well thought out because selling pottery is selling and this blurp on a facebook page I would see as something toward that goal. I think either Mea Rhee or Chris Campbell pointed out in one post how much it mattered to be in an upbeat mood at the worst of shows or what little sales you are getting will dissipate.
I think another great place for something like this is on the bag or box that a customer takes with a purchase because they may well be giving it to someone and we should be trying to market to that person as well because they too may be new to what we do.