I my city we have to large supermarkets very close to each other with an optional self-checkout. In one supermarket there is still a person who helps shoppers w

I my city we have to large supermarkets very close to each other with an optional self-checkout. In one supermarket there is still a person who helps shoppers when they are using the self-checkout the first time or hit a problem like the age verification. The other supermarket doesn't have that person and instead some other personell from the supermarket can be rung for, which takes ages. Want to guess in which supermarket the system is used constantly? One person overseeing four self-checkouts does work, but you still need that one person.