Digital banking has changed how people move money. It has not removed the need for cash, or the expectation that a machine on a street or in a lobby will work. Uptime is the measure of that expectation being met.
The cost of a dark screen
A customer who cannot withdraw cash does not file a hardware ticket. They leave. Repeated failures train the public to distrust a location. For a bank, that is a brand and service problem, not only an operations metric.
Uptime is a system property
Hardware quality, cash replenishment, connectivity, software, and field response all contribute. Improving only one of them leaves the others to create downtime. That is why integrated infrastructure is operationally simpler than a chain of vendors.