It does work, however Wix CRM will only work with Contacts that are in your Contacts list through your Wix Dashboard.
If those Contacts have since been registered for your site and are now classed as site members, then you can’t use Wix CRM to do this, you will need to use Wix Users.
What’s the difference between wix-crm and wix-users?
The CRM API contains functionality for working with your site’s contacts. The Users API contains functionality for working with users who are logged-in members. Note that all members are also contacts, but contacts are not necessarily members.
Note
You cannot use the createContact() function to update contact information for existing site members. You can use use it to update other site contacts.
Have a read of API references and all functions here, which includes the backend versions too.
https://www.wix.com/corvid/reference/wix-crm.html
https://www.wix.com/corvid/reference/wix-crm-backend.html
https://www.wix.com/corvid/reference/wix-users.html
https://www.wix.com/corvid/reference/wix-users-backend.html
Especially when you have lines like this in createContact() info.
The passed ContactInfo object must contain at least one email address or phone number.
Also, note that if you use createContact() then you use Wix CRM. However, if you use updateContact(), then you are using Wix CRM Backend.