Unless you are building a museum item that will never see the water I think it’s good to see a weathered boat.
To quote the film “The Cruel Sea” it is cruel and unforgiving and causes a lot of damage and such like.
When I sail a new one where appropriate on the type of boat I will deliberately sail it thru all the surface flotsam especially any grime or surface oil just so it sticks to the hull.The best weathering in the world it’s natural.
As for rust effect.I know I have mentioned it before but I keep a jam jar full of metal nails,screws and wire wool full of water.Makes the best rust in the world.Paint it on and then a light varnish so it won’t wash off.
Take care all.