You always have to balance development time and run time.
You can always prototype in python, and pass it along to someone else to do in C or C++ if performance needs require. I hate doing things twice.
Sure, that’s the first thing to consider if you have the option. When you’re writing something for say an Arduino, you don’t always have an option. Then there are larger projects where you may need to use many different tools (e.g., php, mysql, javascript, & python).