In shops today these sort of screens are now very popular with our clients partly because prices have dropped.
They also as they are raised, they use little space on the counter and have a screen for the customer. They also look very nice, an vital consideration in retail. As they are made for retail, they tend to work better in retail environments. They are designed with dirty, more prolonged use (retailer commonly use a screen 12 hours a day, seven days a week some more), have higher temperature ranges than the regular screens that are designed for airconditioned offices and as they are closed off and raised the occasional coffee spill affects them little.
Once you get used to touch, the higher speed and ease of use, means you use little else in the cash register.
The operator often needs to watch that they have dry hands. Sweat is an excellent electric conductor, and touch screens do not like sweaty hands or wet fingers. Which in many retail environments can be a problem. Although we were promised that the newer monitors were supposed to be coming out that would be waterproof with wet finger tracking, I have not seen them. Although I have seen some mobiles that have this function.
Still, it is not a big problem, a tissue box nearby fixs it, as does a wipe on a shirt, worst case you find a dry finger. I find my little finger is the least likely to be sweaty or oily. Maybe that is why no-one has done much about the problem of wet finger tracking in retail.
If you are looking to get or upgrade a monitor, I suggest you look into these.