For
It preserves beauty and prevents decay.
Against
It can erase original details and artist’s intent.
Anonymous excerpts, translated where noted.
“Restoration repairs damage and wear in an attempt to return a painting to the state the artist left it.”
“You need to repair damaged art to conserve it and stop it from getting worse.”
“Restoration can add what is not there, and overpainting original paint is educationally and physically damaging.”
“Damage is part of a painting's history and shows what it has endured.”