Pros
Earn a little cash selling products you use yourself. If you're into more of the crafty stuff you can work as a floor operator. If you're only into fine arts supplies, working as a frame shop employee will teach you framing skills, and at the store that I worked at they also had the frame shop people help out with the fine arts supplies: oils, acrylics, brushes, pastels, etc. Getting a discount on art supplies is also a nice bonus, though it ends up being about the same cost as some local smaller stores after the employee discount. Oh well.
Cons
Its a retail job. It pays like a retail job, and you'll get the customers every now and then that view you are a lesser being for holding a retail job. At the store I worked at, in the frame shop, the employees don't care enough about their work. They do a crappy job and whoever is working the day that the customer comes to pick of their frame has to deal with an unhappy customer and make apologies for their stupid coworker. The employees blame other employees for their crappy work. All employees have to take turns cleaning the bathrooms.