Not sure who would buy it full price but in most of the apps if you're not picky there's always some amount of deals to get a meal under $5. I only go occasionally as the deals aren't as good as they used to be across the board and the quality is universally terrible. Taco Bell is also its own unique thing which no other Mexican restaurant will get you so occasionally it just sounds good.
That being said in my area you can go to nearly any proper restaurant and get carry-out under $15 with Texas sized portions. As someone with an unhealthy work/life balance particularly in the evenings, this or bulk curry is how I usually eat dinner.
With a laptop and phone which both can use it my backpack while travelling is so much lighter and less bulky. For me it absolutely was a game changer, I just don't like that I need to carry a USB a to C adapter for all the legacy USB A ports.