M10 and M20 is a amazon exclusive product or will it be available offline too??

M20 is launched at price 12990 for 64 GB version whereas J8 is something 15990 ,such a major difference whereas features are...Does Snapdragon 450 makes J8 that value?Which one is better?

I had been using Galaxy J3 Pro since last 15 months but it still runs on Android 5.0,  will it ever get update or it's not supposed to get. 

Fingerprint sensor of my Galaxy J8 is not instant as compared to MI phones, don't know that problem is with my device only or with every samsung device, as I found one complaining the same at service center.