I’m not involved with ACF beyond the support forum. I don’t know why the developer chose the html style that he did for the HTML. Possible it has something to do with other code that’s included like select2. For what it’s worth, the same effect should be achievable with different CSS and targeting the span rather than the label. If you’d like to request that the developer change this the best way to get a request to him is to open a new support ticket https://support.advancedcustomfields.com/new-ticket/
