As per our rule Do you know when to use CheckBox?. Checkboxes should be used instead of the option group since the answer is a boolean type.
❌ Figure: Bad Example - By default CRM uses option group for contact's and account's contact methods.
You can change the option group to checkboxes by:
Figure: Select and change the email field's properties.
Figure: Change layout and control formatting of email field to one column type and check box.
✅ Figure: Good example - Checkboxes are used for contact methods because they're clear and simple.