Internships, even unpaid internships, are extremely competitive and often go to people who already have experience. Even getting work on places like Fiverr and Upwork, where your experience isn't easily transferrable off the site, is extremely challenging for those starting out. There are beginner lawyers who offer pro-bono services in return for mandatory testimonials, social media posts, etc in place of payment for successful completion of their services. This practice is not limited to lawyers. With this service, we are trying to make this practice easier for people. The ethical concerns you raise are valid. However, from students who have been looking for something like this, we've gotten nothing but gratitude. In addition, this process blinds companies from screening people on the front-end unfairly and requires their judgment to be based on no factor other than the quality of one’s work. The fact is that there aren't enough apprenticeships and internships to go around; we are trying to solve that problem.
As for landev's concern about us charging companies - we have a free option that is intentionally limited to protect against people who would seek to exploit the system. Those who wish to complete projects are doing so because they are looking for non-financial compensation. There are plenty other sites where they can go if their primary goal is to make money for their skills in the short-term.
I will admit, our copywriting was not characteristic of our intentions; we have since changed this to better reflect the type of people we want using the platform.