Jbuilder named attributes vs `extract!`

main.rb

require "bundler/inline"

gemfile do
  gem "benchmark-ips"
  gem "jbuilder"
  gem "activesupport", require: ["active_support"]
end

class User
  attr_accessor :id, :name, :email, :password, :age, :username
  def initialize(attributes={})
    attributes.each do |key, value|
      instance_variable_set("@#{key}", value)
    end
  end
end

user = User.new({
  id: 1,
  name: "User name",
  username: "username",
  email: "User email",
  password: "User password",
  age: 50,
})
Benchmark.ips do |test|
  test.report("named") do
    Jbuilder.new do |json|
      json.id user.id
      json.name user.name
      json.username user.username
      json.email user.email
      json.password user.password
      json.age user.age
    end.target!
  end
  test.report(".extract!") do
    Jbuilder.new do |json|
      json.(user, :id, :name, :username, :email, :password, :age)
    end.target!
  end
end

results.txt

Warming up --------------------------------------
               named    12.273k i/100ms
           .extract!    14.050k i/100ms
Calculating -------------------------------------
               named    129.049k (± 2.5%) i/s -    650.469k in   5.043950s
           .extract!    142.074k (± 2.1%) i/s -    716.550k in   5.045696s