These days you have to send out ton of proposals to start working with real clients. We want to help you skip that part. For that you make a portfolio project for us and get initial traction. I.e. yes, we suggest you to work for free for the first time.
It helps you get used to the process on Upwork without extra tension related to the fact, that you're not sure, if you will succeed with the project or not
Afterwards it's gonna be easier to find real clients paying money for your work.