There are USB NFC readers. Someone could add support for that to Klipper.

It can. All standard spec NFC: https://specs.openprinttag.org/#/nfc_data_format

So any USB or GPIO reader would work. This will be in Klipper quick I bet.

I'm sure the likes of Bambu will never support this, but lots of other makes likely will. Some will jump all in right away (it is cheap and a useful feature for their customers), others will jump in when forced. Some of the cheap ones will never jump in because that is $.50 they don't want to spend.

If the tag is read-only, it can allow:

• marginally better loading, as the printer can heat the nozzle correctly for that filament without input from the user.
• Comparing a G-code file to the loaded filament, either to throw a filament mismatch error, or to adjust temperature settings on the fly.
• Allow slicer software with a network or serial attachment to the printer sense what filament is loaded

If the tag is writable, it can allow for keeping track of how much filament remains on the spool, by writing how much was consumed during each print. This means, when you get to the end of the spool, the printer can warn you if there isn't enough filament remaining without having to manually track the mass of the spool.

By itself, it's does not solve anything.

However it gives some extra data that can be used by the printer firmware.

The NFC tag contains data about the right printing temperatures, the color, the amount of filament left in there spool ...

So a lot of QOL features can be developed with that. For example

• having a message of the amount of filament left in not enough to finish the print I'm about to start,
• auto adjust temperatures depending on the loaded filament,
• importing a library of available filament in the slicer just by taping the spool on the NFC reader.
• using this library of filament for multicolor/multi material printing. So instead of printing selecting each head individually in the slicer and then having to remember to load the right filament, right color in each head you can just select the filament you actually want and the printer will manage.

As a novice with a bambu lab printer, the rfid has saved me and my wife a couple of times from messing up with the wrong settings. Most of what we have is pla but the occasional petg and abs cause a surprise.