when would you want attr_writer in ruby code example

Example 1: ruby attr_writer example

class Person
  attr_reader :name, :age, :sex, :email
  attr_writer :name, :age, :sex, :email

  def initialize(name)
    @name = name
  end
end

Example 2: ruby attr_writer example

class Person
  attr_reader :name
  attr_writer :name

  def initialize(name)
    @name = name
  end
end

john = Person.new("John")
john.name = "Jim"
puts john.name # => Jim