NFC tags are not considered mandatory attributes, without which it is impossible to exist the phone, etc. devices.
They are designed for greater ease of use of the program Smart Connect. Ie, set up modes and then just lean against the programmed tag on a certain mode and he will turn on or off, depending on settings.
Actually, it's my husband wanted to "play" and buy Sony Xperia SmartTags NFC Connect, because I do not use Smart Connect, I find it easier to do most everything in the phone (I think this is a more reliable way). And I don't like that the program is active when it is opened, and thus, unnecessary consumption of the battery. I'm too practical in this regard.
And yet, we bought them.
In a set of four, bright colors. They are made from solid, thick plastic, with a glossy, beautiful finish. In General, their design constantly updated, but, whatever it was, it is still suitable for any model of Sony (and maybe other manufacturers, too – I don't know)
Shared with my husband and two pieces each, this is enough.
Sony Xperia SmartTags NFC Connect can be hung (though in my version of nt2 no lace, but in the new model nt3 it is already there), but you can stick the attached double-sided very thin tape. Husband of one stuck on a tape in the car, on the panel.
In General, in some cases convenient accessory.
P. S. My reviews on equipment and techniques.