why we use fails method in laravel code example

Example 1: $errors show this error in laravel

<input type="text" name="firstname">
@if($errors->has('firstname'))
    <div class="error">{{ $errors->first('firstname') }}</div>
@endif

Example 2: laravel throw function

public function isValid($value)
{
    try {
        // Validate the value...
    } catch (Throwable $e) {
        report($e);

        return false;
    }
}