Why would they sweat? You just input the amount of the check, stick it in the machine to get franked, and the till opens. It’s not much more complicated than cash and way easier than damn WIC (great program, lousy execution).
Handing them a check isn’t a problem. What sucks is when the customer pulls OUT the check book to slowly fill it out, AFTER you told them the total, while your line backs up and it fucks your metrics.