I’ve used it to fix regressions, most recently in a register allocator for a compiler. There’s pretty much no chance I would’ve found that particular bug otherwise; it was caused by an innocuous change (one of those “this shouldn’t matter” things) clashing badly with an incorrect assumption baked into a completely different part of the allocator.

I had seen the same effect from an unrelated bug on a different program. When I added a new test and saw the same effect, I had a “didn’t I fix this already?” moment. When I saw that the previous fix was still there, I checked if an older version of the allocator exhibited the same bug on the new test, and it did not. Bisecting found the offending change relatively quickly and further conventional testing exposed the incorrect assumption.

Learning how to program in any language will make it easier to pick up any other language, because the main burden for a beginner is how to think programmatically. However once you’re enough past that wall, being an expert on one language will mostly only help pick up languages that are similar. So if you knew C++, you could pick up the syntax and probably most of the semantics of the others very quickly, because they are similar in that regard. But you’d still probably struggle to actually program in C, because C is lower level (has way fewer features) than C++.

Technically speaking, C is a subset of C++. But that doesn’t mean being a good C++ programmer automatically makes you a good C programmer.

If you want to make simpler games, you could start with scratch or stencyl. These tools aren’t really programming languages per se but they let you build programs out of blocks that are much easier to visualize and play around with. There’s some research that suggests they are good entry languages and some research that suggests they aren’t, so ymmv. I’ve used both, but I knew how to program already.

For the record you shouldn’t let “usually made with” drive your decisions. Java is still popular for some games. Slay the spire, a very popular deck building game, was written in Java, which is a decently popular choice if you want to support modding. But C++ and C# are more popular simply because that’s what you use if you’re using engines like unity or unreal.

side note: C, C++, and C# are all different languages.