You're totally right and I agree too :) I forgot Deques (and DS) were via PECL.

It's a poor example to give in relation to the article's real-world cases. Nonetheless, it is relevant to queue theory, and knowledge of how, why, and when these data structures can be more optimal than simple arrays has helped me more broadly in the past.

A much more real-world example would be Laravel Horizon, which uses Redis queues to build scalable distributed systems very easily. The last time I set it up I think it took me 5 minutes at most... https://laravel.com/docs/10.x/horizon