Initially, I attempted to use [] or [()] data binding without success, resulting in a less than ideal workaround. For further clarification on why data binding is not functioning in the column template, I recommend consulting with ng-lighting.
For reference, you can view the Plunker here: https://plnkr.co/edit/zNrWb4Ui2LVXc5fJb1oY?p=preview
Below is the additional code I implemented:
<ngl-datatable-column heading="" key="points">
<template nglDatatableHeading><input type="checkbox" (click)="toggleCheckAll()" /></template>
<template nglDatatableCell><input type="checkbox" class="child-chkbox" /></template>
</ngl-datatable-column>
toggleCheckAll(){
var chkboxes = document.getElementsByClassName('child-chkbox');
this.checkAll = !this.checkAll;
for(let i = 0; i < chkboxes.length; i++){
chkboxes[i].checked = this.checkAll;
}
}