Google has deprecated many of the NFC API functions used by the NFC component according to MIT. That means that sooner or later parts of the component will not be usable. When? Maybe next month, maybe next year. What happens depends on what Google decides to do and whether MIT will upgrade the NFC tool it provides. Evan says “developers may want to look for an alternative solution as it (the NFC) may not be around in a few years”. He is speculating; he does not know for sure.
Will there be another way to read and write nfc tag? I do not know . You might read these articles.
Evan indicates that some (but perhaps not all) of the capabilities of the NFC component might have issues as Google deprecates the api.
In the meanwhile, enjoy using the tool.