"He" clocks in at two characters, it's a very concise way of referring to an arbitrary person. "The user" takes longer to write and longer to say. Forcing the reader to juggle around "or" conditions (i.e. with "he or she") is even worse and I consider it bad practice. Your readers will thank you for concreteness and brevity.

You’ll notice that my previous post uses “they” as shorthand for “the user”. If your last remaining argument is that “he” is 2 letters and “they” is 4 and thus it’s unequivocally better to always use “he”, it’s not a very good one.