Indeed. If free-text SMS was an ideal way to interact with online delivery and concierge services you'd think someone would have done that already on an existing service. So then, why can't I just order from Seamless or Instacart via SMS? Oh right, because that experience sucks mightily. I have this lovely full color screen that can display menus, location and delivery times, let me search by cuisine, choose various…
The value proposition: People can fire-and-forget an order for anything. Someone else handles the details. People with more money than time -- a great market to serve -- prefer to trade the former for the latter. Cheapo McCouponClipper will sift through the apps individually.
Do you go to the grocery store and tut-tut people in line? Don't they know they can get batteries cheaper at BatteryWorld? Vegetables cheaper at the farmer's market? Windex cheaper at Bob's Industrial Cleaning supplies? Why are they at a general-purpose store with a larger markup?
But it doesn't matter. The incredulity of objectors who ask "Why don't you just install 20 apps and save some money?" will be superceded by people who just want to use the service.