Benchmark about "recursive regex match?" vs "recursive my own match?"

benchmark.rb

require 'bundler/inline'

gemfile(true) do
  ruby '~> 2.5'
  source 'https://rubygems.org'
  gem 'benchmark-ips'
end

require 'benchmark/ips'

BALANCED   = '(a)(b)((c))'.freeze
UNBALANCED = '(a)(b)(c))'.freeze

COMPLEX_REGEX = /\A(?<paren>\([^()]*\g<paren>*\))*\z/x.freeze
SIMPLE_REGEX  = /(\([^()]\))+/x.freeze

def my_match?(string)
  string = string.dup
  captured = string.gsub!(SIMPLE_REGEX, '')
  # string.strip!
  if captured.nil?
    true
  elsif captured == ''
    false
  else
    my_match?(string)
  end
end

Benchmark.ips do |x|
  x.report('recursive regex using ruby match? method - positive case') do
    BALANCED.match?(COMPLEX_REGEX)
  end

  x.report('recursive regex using ruby match? method - negative case') do
    UNBALANCED.match?(COMPLEX_REGEX)
  end

  x.report('recursive method using my_match? method - positive case') do
    my_match?(BALANCED)
  end

  x.report('recursive method using my_match? method - negative case') do
    my_match?(UNBALANCED)
  end

  x.compare!
end

result.txt

Fetching gem metadata from https://rubygems.org/.
Resolving dependencies...
Using benchmark-ips 2.7.2
Using bundler 1.17.2
Warming up --------------------------------------
recursive regex using ruby match? method - positive case
                       122.483k i/100ms
recursive regex using ruby match? method - negative case
                       128.298k i/100ms
recursive method using my_match? method - positive case
                        20.203k i/100ms
recursive method using my_match? method - negative case
                        20.465k i/100ms
Calculating -------------------------------------
recursive regex using ruby match? method - positive case
                          2.032M (± 2.1%) i/s -     10.166M in   5.004149s
recursive regex using ruby match? method - negative case
                          1.975M (± 3.1%) i/s -      9.879M in   5.006411s
recursive method using my_match? method - positive case
                        229.712k (± 5.3%) i/s -      1.152M in   5.026184s
recursive method using my_match? method - negative case
                        231.356k (± 5.1%) i/s -      1.167M in   5.054504s

Comparison:
recursive regex using ruby match? method - positive case:  2032494.3 i/s
recursive regex using ruby match? method - negative case:  1975252.4 i/s - same-ish: difference falls within error
recursive method using my_match? method - negative case:   231355.9 i/s - 8.79x  slower
recursive method using my_match? method - positive case:   229711.9 i/s - 8.85x  slower