throwaway185205

If I can trust 2018 OAuth-as-a-service vendor literature, it seems popular to signify "use grant flow X because your app has no backend."

Do you, personally, more often receive packages, or junk mail?

Extrapolate.

What? USPS is the single largest parcel carrier in the US

They're the only unsolicited advertisement carrier in the US.

"Hello, merchant? I haven't received my package, but the tracking info says it was delivered at 9:00."

Do you know what the merchant says, because they deal with this _all the time_?

USPS functions almost exclusively to deliver unsolicited advertisements. Its "delivery confirmation" is outright fraud.