Well 95% of Papa John's are franchised rather than corporate-owned company stores, so there's a very good chance that the purchase of your Papa John's pizza supported a local business owner, and a 100% chance that it supported local employees.
So, good on you, you bought local just as your friends urged you to do!
I find myself split on this.
On the one hand, these things are true. But, spiritually it feels weird. Like if I said, that place has a lot of local restaurants, all Dominos and Subways, that would feel weird.
In any case, folks will do what they gotta and I won't judge. I'm in part throwing money toward non-chain local restaurants because I like what they do, and since I only have so much money, if I can contribute to keeping a unique sandwich place standing, I'd prefer that to ensuring one of the seven Papa Johns near me stays open.
Maybe it's because I fear if a non-franchise goes under, it will not return, whereas if a franchise does, it not only will return, but will mostly just change a drive to pick up or delivery process. That feels harsh to the unique people who run those restaurants, but the product they sell is of course not unique.
Anyway, food for thought.