I have one. Unless you use NFC tags (or even know what they are), they serve no other purpose other than making your keyfob look cool. 
Not sure what you mean, I have a iPhone so is it good or bad?No good if your a iPhone user they basically switches to toggle settings/apps to,open on your phone
If you have an iPhone it is 100% cosmetic. If you have an Android phone with NFC support, there is a tag built into it you can use to trigger certain things on your phone, but even then I don't know many people that actually use those.Not sure what you mean, I have a iPhone so is it good or bad?