Google Quietly Discontinues NFC Smart Unlock Without Explanation (betanews.com)
Mark Wilson writes: Android users have been slowly discovering that Google has killed off NFC Smart Unlock. The feature, which makes it possible to unlock a phone with an NFC device such as a ring or bracelet, has been discontinued without explanation. Earlier in the month, Android users started to post messages on Google's Issue Tracker website, indicating that the feature was no longer available to them. Three weeks later, Google has finally responded, indicating that NFC Smart Unlock has been deprecated.
It seems to me at that point I'd rather side-load a free software app that can do the same thing, so that I can't have the rug pulled out from under me.
100% this. If I have to rely on the whims of a company to continue using a product, I won't use that product for anything that is actually important to me. And yes, I keep copies of the apks I use on my phone, just in case.