Sanders offers an implicit challenge to the current system of national electoral politics. With rare exceptions, campaign season is a time when the backroom favorites of financial interests are marketed to the population. Weighed down by highly regressive policy intentions, these candidates need huge laboratories of focus groups and image consultants to guide them as they grope around for a few lines they can use to sell themselves to regular working people.Nah. Sanders is in specifically because he poses absolutely no challenge, implicit or explicit, to anything. Instead, he is a marketing gimmick thrown in there just to give dissenting liberals something to talk about for a few months so that they'll leave Hillary alone while she's busy getting ready to run the real campaign.
Sanders on the other hand has no constituency among the monied crowd. "Billionaires do not flock to my campaign," he quipped. So what his race is about is the reverse of the usual process: he'll be marketing the interests of regular people to the gatekeeping Washington press, in the hope that they will give his ideas a fair shot.
And yes that is indeed better than nothing. But it's also not a significant something.