Greek alphabet sorting seems a little bit wonky.
It goes well but words that start from Π (Pi) go to the end of the list for some reason.
(Also words with acute accent are out of order)
PHP sorting seems okay, so it must be a kirby thing. 
home.php
<h1><?= $page->title() ?></h1>
<ul>
<?php foreach ($page->people()->toStructure()->sort('name', 'asc') as $p) : ?>
<li><?= $p->name() ?></li>
<?php endforeach ?>
</ul>
<?php
$names = array("Ανέστης", "Βασίλης", "Γιάννης", "Zelda", "Δημήτρης", "Ελένη", "Ζωή", "Ηλίας", "Θωμάς", "Dean", "Ιωάννα", "Κατερίνα", "Cindy", "Λουκάς", "Μαρία", "Νίκος", "Ξανθή", "Ορφέας", "Παναγιώτης", "Ραφαήλ", "Amanda", "Σοφία", "Τάσος", "Υπατία", "Φίλιππος", "Χρήστος", "Ψαρρής", "Ωραία", "Bill");
sort($names);
echo '<pre>'; print_r($names); echo '</pre>';
?>
home.txt
Title: Home
----
Text:
----
People:
-
name: Ανέστης
-
name: Βασίλης
-
name: Γιάννης
-
name: Zelda
-
name: Δημήτρης
-
name: Ελένη
-
name: Ζωή
-
name: Ηλίας
-
name: Θωμάς
-
name: Dean
-
name: Ιωάννα
-
name: Κατερίνα
-
name: Cindy
-
name: Λουκάς
-
name: Μαρία
-
name: Νίκος
-
name: Ξανθή
-
name: Ορφέας
-
name: Παναγιώτης
-
name: Ραφαήλ
-
name: Amanda
-
name: Σοφία
-
name: Τάσος
-
name: Υπατία
-
name: Φίλιππος
-
name: Χρήστος
-
name: Ψαρρής
-
name: Ωραία
-
name: Bill
home.yml
title: Home
columns:
main:
width: 2/3
sections:
fields:
type: fields
fields:
text:
type: text
people:
type: structure
fields:
name:
type: text