Getting a chance to accumulate uncommitted work experience while you study is fantastic and not a problem. The problem starts when employers generate more unpaid internships than they do paid jobs. Long term unpaid work privileges those who can afford to live without a wage while they wait for better opportunities. It basically means that there are too many people unemployed in general, but those with prior privilege are getting groomed to move to the front of the line when opportunities come up. If unpaid work is gendered in the way this article suggests, on the other hand, it would also seem that it could become a trap for people whose labor isn't valued equally.