I know Walmart has them, it's kinda necessary considering the size of some of the products they sell.

Perhaps. I've seen many, and they're wireless. I suppose they might end up missing.

We have hand scanners at the local grocery chains HyVee and Dillon's (owned by Kroger) that are doing just fine. Lowe's and Home Depot have hand scanners too. They have all sorted out all the 'unexpected item in baggage area' and other stuff years ago.

No idea about Walmart, but could see that type of store going cheap on the hardware and having it treated terribly.

It's fairly new in my area, but it's great. That and contactless payments (Google and Apple Pay) are nice.

Every self checkout I've used has a hand scanner. Scanning your own things is so much faster. I fail to understand why people whose job it is to check people out all day are so slow at it.

Then you get the customers that want to have a conversation with the checkout clerk. I'm sure the checkout person doesn't care that your grandfather has the same name and he was name after his great grandfather who rode the rails across the expanding United States in the 1800s.