Why is *ngIf not working when a variable is settled to 0?

I have 3 input fields with [(ngModel)] to 3 variables.

Then I have a hidden button that only appears when all 3 variables have a value, using *ngIf. Check out the code:

<mat-form-field>
    <input matInput [matDatepicker]="picker" placeholder="Fecha" [(ngModel)]="matchDay">
    <mat-datepicker-toggle matSuffix [for]="picker"></mat-datepicker-toggle>
    <mat-datepicker #picker></mat-datepicker>
</mat-form-field>
<mat-form-field>
        <input matInput placeholder="Hora" type="number" min='00' max='23' [(ngModel)]="matchHours">
</mat-form-field>
<mat-form-field>
        <input matInput placeholder="Minutos" type="number" min='00' max='59' [(ngModel)]="matchMinutes">
</mat-form-field>
<div class="button-row" *ngIf="matchHours && matchDay && matchMinutes">
        <button mat-raised-button color="accent" (click)="setMatchDate()">Set Date</button>
</div>

The problem is that if "matchHours" or "matchMinutes" have 0 or 00 value, the "Set Date" button does not appear as if the *ngIf condition was not met.

Any ideas what might be happening here?

Here is the ts code:

export class CreateMatchComponent implements OnInit {

  matchDay: Date;
  matchHours: number;
  matchMinutes: number;

setMatchDate() {
    let parsedDate = this.matchDay.toISOString().split('T');
    this.match.matchDate = this.createFormattedMatchDate(parsedDate[0], this.matchHours, this.matchMinutes);
    console.log(this.match.matchDate);
  }

  createFormattedMatchDate(parsedDate: string, hour: number, minute: number) {
    minute = pad(minute);
    hour = pad(hour);
    function pad(n) {
      return (n < 10 && n >= 0) ? ("0" + n) : n;
    }
    let formattedDate = parsedDate + "T" + (hour + 3) + ":" + minute + ":00";
    return formattedDate; 
  } 
}