When do we MUST use "condition" function in php?

Question

I knew that we use continue to jump to the next iteration in loop

For example

$x = 0;
for( $i = 0; $i < 10; $i++ ) {
  if( $i%2 == 0 ) {
    continue;
  }
  $x = $x + $i;
}

In this case we use continue to skip the even number, but we can do this instead

$x = 0;
for( $i = 0; $i < 10; $i++ ) {
  if( $i%2 != 0 ) {
    $x = $x + $i;
  }
}

Can anyone show me some cases that we MUST use continue instead of only using opposite condition.