Why prefer ActiveRecord `attribute=`

client.rb

User.create(username: 'jdoe', name: 'John Doe')
User.find_by_name('John Doe')

user-v1.rb

# create table user (
#   id int,
#   username varchar(12),
#   name varchar(255),
#   updated_at timestamp with time zone,
#   created_at timestamp with time zone
# )
class User < ActiveRecord::Base
end

user-v2.rb

# alter table users add column (first_name varchar(255))
# alter table users rename column name last_name
class User < ActiveRecord::Base
  def split_name(name)
    # TODO something fancy
    name.split(/\s+/, 2)
  end
  
  def name=(name)
    fn, ln = split_name(name)
    write_attribute(:first_name, fn)
    write_attribute(:last_name, ln)
  end
  
  def find_by_name(name)
    find_by_first_name_and_last_name(*split_name(name))
  end
end