No one suggested that every single store should have its own app.
However, it's clear that regular customers to a (major) store have no problem using a store specific app if it gives extra time or money savings.
I think Starbucks has more people using its app than Apple Pay, for instance. Taco Bell has found that people pre-order much more food using their app. And so forth.
Myself, I just downloaded the CVS app because I pick up a lot of prescriptions, and it apparently can help me check out faster, especially at the drive-up where I can sign for medication right there on my phone.