We often use the machines to check out in the supermarket, and notice that they now have TV cameras showing your face on them.

I wonder if this will be eventually used for identifying you with a link to your bank account saving even more hassle and fumbling to pay for your groceries?

Another possibility is to automatically determine whether you are old enough to buy alcohol or other products. At 81 I'd have thought it obvious in my case, but I still get asked asked occasionally if I'm old enough to buy alcohol. Usually, I reply its for my grandfather who is playing rugby at the moment.

I like the idea of being recognised for payment and plan to wear an Elon Musk mask.

Some time ago (probably a decade or more) I was in Argos, I did my stock check on the little machines and wrote the items on paper, then went to the paypoint which immediately put the list of items I had stock checked on the screen. It had clearly tracked me as I could have come from any machine and gone to any paypoint.

I believe trials have done on retinal scan payments but these have been hesitant because of the ease of production of imaged contact lenses which could fool the machine and not be obvious to any assistant.

Any visual recognition system is reasonably fool-able (after all, you look identical to a younger Elon Musk) and there needs to be a separate disconnected confirmation for any financial transactions. Although you hear some ridiculous figures of accuracy, products actually in the marketplace only have few false positives when they have increased false negatives, general purpose accuracy of practical solutions isn't there yet.

A bit unrelated but fingerprint detection on things like mobile phones is widely used but there is a huge flaw in that in practice, if you give me somebody's phone, somewhere around 70% of the time it can be fooled in a couple of seconds without having any connection whatsoever with the person whose fingerprint is correct and without using any electronic equipment. It is so simple I have done it myself unintentionally on occasions. Visual systems always have flaws.

Brain implants are in progress, they will eventually be the norm and be very nearly fool-proof.