Copy content via GUI, by clicking a button?

I don't think this is worth doing for the reason that field updates like this should really be handled in an update hook. Noone would (should) ever really perform this on a live site. I can improve the drush commands however to simplify the steps.

Thanks for replying, though, even if it shouldn't be done on a live site, having the button would be nice.

After all, Drupal migration in the browser → has a button, right? I think the button could be added, with a caveat "Not recommended for live sites".

It could also serve as an easier introduction to the module, for users who are experimenting with it in a Drupal sandbox installation.

Also, please remember that a large number of Drupal site builders cannot program an update hook. So I think we should make it easier for them, by not only highlighting the Drush option in the Quick Start on the project page, but also adding a button. Thanks!

Adding related issue about giving Drush more prominence in the Quick Start, while still mentioning the update hook option for the expert developers.

FWIW, i'm updating the drush command to provide interactive prompt for selecting the updater entity and returning an example update script in the response. For now, I'm going to limit this functionality to Drush as its quite trivial for anyone to run the command for local testing. This module was always intended for a developer audience.

Automating code writing and speeding up development is always nice, and sounds like a cool feature. And I do hear you ("This module was always intended for a developer audience.").

But the thing is, being able to easily transfer data from one field to another is a killer feature, that a lot of Drupal users can find extremely useful. And only a minority of those who can use this feature will be developers, but more like site builders, and (like I wrote) not able, nor in need of writing an update hook. Many of them also cannot write migrations, and this module can solve the task of transferring data, easily.

So I think it should be made clearer, that it's actually really easy to transfer data from one field to another with this module. The developers will have no problem scanning the project page, and see that update hooks are an option.