Well yeah it's probably not actually useful right now for establishment dems to use it. Occupy Wall Street helped popularize the idea of the 99% vs the 1%, I think that sort of language is more useful for encouraging unity among the working class.
Like describing workers vs the owner class or something along those lines, there are many ways to explain marxist/socialist concepts with simple, easy to grasp language that isn't stained with the connotations of 'communism' that many Americans are instinctively opposed to due to decades of red scare propaganda.
That sounds sketchy, I've seen card only but where have you seen a business do this?