I believe there's discounts only if you use their app, so they can monetize you with surveillance. It's still garbage food, though. I can't imagine what the $5 tier is like.
It's the same food but in smaller portions, which sounds more appealing to me. I wish more places had appropriately sized & priced portions of food instead of "here's 2500 calories and a drink with enough sugar to give you diabetes for $10".
Sometimes I get random cravings for certain fast foods, but I always feel like a sucker when I opt to get less food but pay almost the exact same. The idea of getting the bigger sizes of fast food and reheating leftovers makes my stomach churn a little, though, haha.