The Vue native ComboBox and Autocomplete do not support the value-render prop and slot, so a selected value cannot have a custom display. The DropDownList does however - they should all be consistent in this.

DropDownList reference:
https://www.telerik.com/kendo-vue-ui/components/dropdowns/dropdownlist/custom-rendering/#toc-values

Any chance we'll be getting a Vue native version of the MultiColumnComboBox?  This is a very useful control :)