Two examples of times I have used Greek letter variable names: (a) Often times the Greek letter is the standard way of referring to a concept, e.g. "beta" in a

Two examples of times I have used Greek letter variable names: (a) Often times the Greek letter is the standard way of referring to a concept, e.g. "beta" in a linear regression. For these situations, the Greek letter would be used in spoken language to refer to the concept and is more clear than trying to describe the underlying concept in English. (b) If you implement a non-trivial mathematical equation, it is clearer to use the variable names which are found in the published equation than to try to rename them. To understand the equation, people will need to read the published description anyway, and it is easier to map one to the other if you don't change the names. Likewise, if you are implementing your own equation, you will usually use Greek letters in the paper, and for consistency, you should use the same variable names in the code as you do in your paper.