Unemployed people can do plenty of things to develop skills, and are often required to do so by welfare programs. What are the main skills acquired by working at Walmart after the first week?
I don't know, never worked at Walmart (and shopped there maybe twice) but I can guess - people skills? Management skills if one becomes, say, shift supervisor? Plain old "showing up to work on time" skills (for a person who never ever held a steady job that might be a new skill too)? Having a resume that actually shows you can do all of the above so hiring you is lower risk?
Developing skills because some law requires you to check the V in the papers and developing skills because you're actually earning your living doing that is a very different thing.