This is similar to a Machine Name module

Machine Name module adds a field type into which the user enters a machine name, it's main function is to validate that the input conforms to the machine name format.

Safeword module provides a standard text field and when text is input displays a matching machine name field which automatically converts the text into a machine name formatted version, which can also be hand edited.

The two modules are very different.

@Robert Castelo Could you please consider stating this difference explicitly on the project main page, giving a link to Machine Name project as well?

Good point - done!