Correct, they display as Yes/No based off the value of 1/0. To display a actual checkmark you could use the following for its Profile Value Layout within Parameters > Layouts of your field.
Code:
[cb:if FIELD_NAME="1"]<span class="fa fa-check text-success"></span>[/cb:if]
[cb:if FIELD_NAME="0"]<span class="fa fa-times text-danger"></span>[/cb:if]
Replace FIELD_NAME with the actual name of the field. CB utilizes fontawesome so you don't have to use check/times, but can use any of the following.
fontawesome.io/icons/