Feature: Should we add "Back Button" functionality?

[kerk12]

Imagine the following:

• You're a user of an app that features a registration form, protected by captcha.
• You type in your details, click on submit. The captcha challenge appears.
• Whoops, you remember you typed something wrong!
• You click the back button.
• The registration form appears again, with all your data typed in. You can now edit the form again and resubmit.

Should we spend some time adding this, or should the user do it themselves using the included CaptchaBloc? Keep in mind that if we are to add this, there should be a toggle functionality for the feature (addBackButtonReturn: true)...