What is the pink „Nearby“ card?

It tells you: you're near a store where you still have open items. pon recognizes the store because you've checked off there before — that's how it learned the spot (all on your device, your location never leaves it). And it only appears when you really do still have something open for that store — otherwise it stays away.

It's meant as a little reminder in passing, so you take care of the shopping right away instead of making a special trip later. You get the most out of it if you allow notifications: then you even get this hint as a push, without having to open pon at all. And when you open the app, you see the same card at a glance up top. The widget and the Apple Watch mirror the same hint.