pros and cons
before the advent of no stretch (or low stretch) line, wire was used, but now halyards made from dyneema, spectra, technora are vastly superior to wire. Wire may develop fishhooks that can hurt hands, sails and the line part of the halyard, it is more difficult to jump at the mast and it is far heavier than all line halyards. It is easier to remove in the off season (replace with a messenger line) to keep dry, out of the sun and to avoid wear and tear (slapping on halyards in the boatyard)