legal paperwork/receipts,
garage access tokens,
home access tokens,
school library reserved room token,
improved certificates of authenticity for collectibles,
augmented reality trading card games,
had to start thinking, so I'll stop there.
Have you deeply considered any of these (the technology part of the technology),
or just today's grifters?
Don't be the one to get everyone to throw away email because of fake princes scamming people through it.