I ended up using a QR code in my (Electron) app: the app runs a server, and you take a photo of the QR code on your phone to open the localhost (accessible only over WiFi). The app lets you browse videos you have on your computer through your phone, and when you click on the video image, the video plays on your computer from the frame you clicked on. It turns your phone into a "remote". Cheers: https://videohubapp.com/ & https://github.com/whyboris/Video-Hub-App & https://github.com/whyboris/Video-Hub-App-remote
Nice. I used them in a poll creator. You create a poll and the app generates a QR code for you to display. People can use the QR code to go to the poll's site and vote.
That's actually similar to the method Nintendo used when they finally added an option to send photos and videos to your smartphone from the Switch, with the addition of a first step where the Switch acts as a wifi hotspot and shows a QR code to quickly connect you to it. Then you scan another QR code that jumps you into a simple webapp running on localhost where you can download the photos/videos
