Do challenge results reflect how good you are at programming?
When I do challenges, I'm better at C++ challenges than Python challenges. I have more wins in C++ than Python. But in the real world, I am more comfortable with programming with Python because that is my first language. So do the challenge results (number of wins and losses) reflect how good you are in programming?
Truthfully no and you just pretty much explained it in a nutshell.
You know your way around the python world in real life... not saying this isn't. Which Python is your strong suite... Cpp is a fallback language where you are not so much using libraries as you are the logical algorithms. You always have been strong competition to those you play in either language... Keep going Cpp but don't hold the storming numbers as a measuring stick as your brain and hands reflect how good you are.
Challenges definitely require some skills. Of course it is useful to know the programming language, they require some programming skills to decipher codes and calculate results. A lot of questions are tricky and you do not need to know the answer even when using the language for a decade because it is not a good coding practice, but it is fun and why not to know even some tricky things from language syntax. Repeating the same stuff again and again can convert short-term memory traces to long-term memory tracks.
On the other hand if you play repeatedly, you start to remember answers, so I think it is a good idea to play in different languages and consider it only as a supplemental part of learning. Good results in challenges do not mean that the person can create complex applications, make proper design decisions etc.