How does `drush features-update` work?
Drush feature-update updates the feature code with overwritten settings. So the function is used to export changes to code.

If you want to take those changes to another site, you will have to copy the updated feature to the other site unless they share the same code (and then revert the feature and clear cache (not always needed)).

In code it could look like this

$ drush fu feature_module
$ cp -r feature_module ./DIR
$ cd DIR
$ drush fr feature_module