Umm nothing yet
You might want to sync two variables, and when one changes, the other changes accordingly (eg: the polar coordinate and cartesian coordinate of a vector). But as programmers we are lazy and we don't want to change each at a time with multiple lines of code. This is how to make it easy and convenient.
- Be able to change and access these properties easily like normal variables or object properties
- Be able to link as many variables as we want
- No constant updating that would cause lag
Python and js are both quite popular. Some python users want to start doing web-dev, which most people used js to do so.
Although many people want to switch to js, some people struggle to do so.