And also shows that the split pin or mousing wire hasn't fallen out. Usually use self-amalgamating tape. Important not to cover all of the bottle screw so that water can drain and corrosion doesn't happen unnoticed.
If its just on the threads...it may be because yr boat yard ( or that of a previous owner) used it to mark the rig 'set up' before taking the mast down.
They would have wrapped it around the thread just above and below the central 'turnbuckle' and then when they or your put the mast up again it can be set straight back to previous tension.
Because the non-UV resistant cheap cable ties will become brittle and will break off when knocked ... then when you're sailing to windward the leeward shroud is slack and the clevis pin drops out ... you tack and find you've reefed rather suddenly.... metal split ring or pin for me ...