Strict_types does not affect array_walk

Question

While working on the following code I noticed that declare(strict_types=1) has no effect on the arguments of a callback function through array_walk()

<?php
declare(strict_types=1);

function myCallBack(int $value, $key) {

    echo $value;
}

function myFunc(int $value, $key) {
    echo $value;
}

$myArr = array("eggs" => 4, "Butter" => 4, "meat" => 4.5);

echo 'myCallBack..';
array_walk($myArr, 'myCallBack'); // Output: 444 

echo ' <br />myFunc..';
myFunc(4.2, 'eggs'); // Output:Fatal error: Uncaught TypeError: Argument 1 passed to myFunc() must be of the type integer

?>

I'm expecting php to throw an exception instead of 444 because [meat] value in $myArr is not integer!

apparently php ignores the fact that [meat] in $myArr is float for some reason! instead of throwing an exception just like what happened with myFunc().

Is this a normal php behavior or am I missing something?.