I feel like people are over complicating this.
Constants are a type of variable which do not change. Once a value has been assigned to a constant, any attempts to change that constant will result in an error.
Whilst Lua doesn’t feature constants, languages such as Swift use constants because it allows for various optimisations to be made, improving the efficiency of your code. We can do this because you would only use a constant when it is certain a value would never need to change during execution of the code.
Examples of this would be the value of a certain mathematical constant, such as Pi, or the group ID of departments for your group.