ng container vs ng template

1<div>
2  Pick your favorite hero
3  (<label><input type="checkbox" checked (change)="showSad = !showSad">show sad</label>)
4</div>
5<select [(ngModel)]="hero">
6  <ng-container *ngFor="let h of heroes">
7    <ng-container *ngIf="showSad || h.emotion !== 'sad'">
8      <option [ngValue]="h">{{h.name}} ({{h.emotion}})</option>
9    </ng-container>
10  </ng-container>
11</select>
12