Every minute your registers are offline is a minute you cannot take orders or payments. For a busy counter, an outage during peak hours is not an inconvenience, it is lost revenue you never get back.
Most point of sale setups depend entirely on the store's main internet connection. If the provider has an outage, or a construction crew cuts a line down the street, the whole front of house goes dark. Staff fall back to pen and paper, payments stall, and the line backs up.
Built-in cellular connectivity changes that equation. When the primary connection fails, devices stay online over a separate network automatically, so checkout keeps running. Customers never see the difference.
Reliability is not a glamorous feature, but it is the one you notice most when it is missing. A system that stays online through an outage pays for itself the first time the internet goes down on a Saturday.