We are happy to publish multi-select menu as a custom user profile field for Moodle.
How it could be useful:
This new custom profile field type could be used in many cases like:
1. You have to differentiate users into groups and one user could be part of multiple groups
2. You want to take inputs from user at the time of registration or you manually want to fill some information for users like education, certificates they have done.
3. There could be various other cases like this.
While, the plugin is under approval process, i would like to know if people are really interested in this?