The point is this: you hand out problems that the kids can solve after some struggle with the problem to give them confidence that they can solve the problems that come their way. That's actually a concept in German pedagogy.
The American way is to drill the kids with an algorithm and then hand them 20 more problems that are solved with the same algorithm, no insight required.
Classic Eastern European pedagogy is different. You give kids problems many /can't/ solve a lot of the time to build resilience.
Kids in the West come out with a fear of failure. Good problems in Western pedagogy are the German style ones, where kids struggle for a bit and then get it, to "build confidence."
Kids in the (Soviet-era) East come out understanding there are problems which are easy to solve, hard to solve, and impossible to solve, and you'll face all three in school and in life. You won't know which one you've got until you've tried.
The American way is to drill the kids with an algorithm and then hand them 20 more problems that are solved with the same algorithm, no insight required.