Agreed. I am a fan of Sam’s Scan-n-Go. It has increased my patronage of the store significantly by reducing a lot of frustration.
I wish Costco had the app as well. I prefer Costco to Sam's, and the checkout lines at Costco, while long moved very fast. But, since COVID, Costco does not keep as many lines open and they try to funnel everybody into the self-checkout lines. If you are buying wine or beer you have to wait until someone comes over to approve the purchase, which holds up the line for everybody else. I may let my Costco membership lapse and keep Sam's.