Importantly Sets have different semantics than Lists. Creating a set is an information losing process. A list converted to set cannot be recovered, but a set converted to a list is easily recovered.

I don't think this is handled well in TFA. Because of some dubious iteration at the call site, the author changes the semantics of getLoadNames(), blithely assuming that duplicates should not be allowed and order is not important.

The author mentions that the function is called at two other places. For all we know the original author was aware of Sets but chose List because it more correctly matched the use of the structure.