PHP Array Returning [object Object]. Tried existing answers results with no luck

Let’s try the below code,

$users = get_all_user_ids('');
$i=0; // initialization 
foreach($users as $user) {
    $pageview = get_user_meta($user, 'page_visits', true);
    if ($pageview != 0) {
        //$popularid[$pageview]['count'] = $user; // Err:  // Array won't be unique due to pageview might be same for multiple users
        // $popularid[$user] = $pageview; // Array will be unique based on user id
         $popularid[$i]['user'] = $user;
         $popularid[$i]['pageview'] = $pageview;
         $i++; // incrementor
    }
}
//rsort($popularid); // Sorts based on value
usort($popularid, function($a, $b) {
   return $a['pageview'] - $b['pageview'];
});
$userArr = array_column($popularid, 'user');
//return $popularid;
return $userArr;

Update:
Core PHP code example for usort

$array[] = array('pageview'=>4,'user'=>'abc');
$array[] = array('pageview'=>2,'user'=>'xyz');
$array[] = array('pageview'=>1,'user'=>'pqrs');
$array[] = array('pageview'=>3,'user'=>'ijk');

usort($array, function($a, $b) {
    return $a['pageview'] - $b['pageview'];
});

$userArr = array_column($array, 'user'); // to get only the values from user key
print_r($userArr);