It is harder for new programmers, but certainly not impossible. It is good to step outside your comfort zone, it is the only way to grow.
A lot of these challenges require research on how to solve the sub problems.
For example a lot of new developers would try to iterate a number using a for loop and find out that doesn't work, then they would do a google search on how to iterate a number and likely find some suggestions and move on to the next problem.
You don't need a lot of experience in development to understand how to break a problem into smaller problems. Turning these smaller problems into code is something you certainly get better at with experience.
Actually writing code that isn't handed to you is the best way to grow and Code Wars provides thousands of unique problems that are not overwhelming and don't involve solving hundreds of problems like a typical real world project would. You just have to write one function. Perfect for a daily routine.
Yes, I agree on getting out of your comfort zone id good and writing your own code / working on a small project is an amazing way to learn!
But it can also be discouraging when you get a problem and you don't understand anything xD
Thats why I think it would be better with a small amount of knownledge, so you at least have an idea of what is going on.
I will 100% use Code Wars in the future!
If you get to a problem and you don't understand anything you likely haven't broken it down small enough.
There are times (and a lot of them) where I feel I am absolutely clueless how to solve a problem.