Why one system tells you exactly which device alarmed — and the other only tells you which zone.
A conventional fire alarm system wires its initiating devices — smoke detectors, heat detectors, pull stations — into zones: a group of devices sharing one electrical circuit. When any device on that zone activates, the panel only knows the zone has an alarm condition. It has no way to tell which specific device inside that zone actually tripped — the display typically reads something plain like "Zone 3 Alarm," and responding personnel have to physically walk the entire zone to find the device that's actually in alarm.
An addressable system gives every individual initiating device its own unique electronic address, communicating with the panel over a Signaling Line Circuit (SLC). When one device activates, the panel identifies exactly which device — and, because every address is mapped to a specific physical location during programming, exactly which room — triggered it. That's the entire tradeoff: conventional systems know somewhere in this zone; addressable systems know this exact device, this exact location. Addressable hardware costs more per device, but device-level granularity is the whole point of the added cost, not an incidental feature.