You checked in a hotel and given a NFC tag to access your room. If you lost your card and someone else had the lost card can access to your room. Wouldn't it be more secure if another piece of information like PIN is required to open the door?
I have made a simple system using Arduino, NFC reader, display panel and keypad just to demonstrate that.
A welcome prompt.
Tag a NFC card to the reader. You will see a greeting and be asked to key in a PIN. If you key in a wrong PIN or did not manage to key in a PIN within 30 seconds, it will show the welcome prompt again.
If you key in a correct PIN, the red LED light will light up.
The light will toggle off with a tag and PIN entry.