Supermarket religion? POC inside

The easy (and lazy) metaphor is to compare a megachurch with a supermarket.
Many journalists, and even some sociologists, have jumped to this conclusion: megachurches would be the religious equivalent of supermarkets.
Really?
I won't open the debate in this short space.
Let's just say that the Mulhouse POC does help those who like to draw this comparison: this megachurch meets in a former supermarket...