I am working on four-point parabolas with the function FourPointParabolas on the Function Repository, and I noticed that the function uses formal variables. For example, I can enter formal x displayed as an X with a dot underneath it with escape period x escape, which is the character's alias. I wonder what the benefit of using a formal variable is aside from its protection. I understand this is a benefit to prevent conflicts with y, and you can use formal y. I'm not familiar with formal variables and have read the documentation at tutorial/MathematicalAndOtherNotation#173509264 under the Formal Symbols section.

For example, if I created a function similar to FourPointParabolas, would it be a good idea to use formal variables instead of any variables?