Example of using tuples instead of array key-value pairs

the-most-common-way.php

class BuildReport
{
    private function getColumnHeaders()
    {
        // Why do you need array keys if this array is private details?
        // It's never exposed outside this class so you have full control of its format
        return [
            ['id' => 'first_name', 'label' => 'First Name'],
            ['id' => 'last_name',  'label' => 'Last Name'],
            ['id' => 'department', 'label' => 'Department'],
        ];
    }

    public function render($records)
    {
        foreach ($this->getColumnHeaders() as $header) {
            $id = $header['id'];
            $label = $header['label'];

            // Do something with $id and label ...
        }
    }
}

tuples.php

class BuildReport
{
    private function getColumnHeaders()
    {
        // If you need to change the data, the changes are confined to this class
        return [
            ['first_name', 'First Name'],
            ['last_name', 'Last Name'],
            ['department', 'Department'],
        ];
    }

    public function render($records)
    {
        // PHP >= 5.5 -- This is the shortest thanks to this feature in 5.5 https://wiki.php.net/rfc/foreachlist
        foreach ($this->getColumnHeaders() as list($id, $label)) {
            // Do something with $id and label ...
        }
        
        // PHP < 5.5 -- This is slightly more code if you're running 5.4 or older
        foreach ($this->getColumnHeaders() as $header) {
            list($id, $label) = $header;

            // Do something with $id and label ...
        }
    }
}

Perhaps this is a bad example, but what do you do when you later on you need to add meta-data to each of these? ex: a class name to certain headers

It seems to me the weakness of a tuple is that by its very definition it is hard-coded to be a pair. I ccan see other examples where this could be desirable - key:values where you might actually like to enforce that pairing, but if that is not the case, you seem to lock yourself into a structure purely because you feel it "looks like nicer code"

Have I completely missed your point?