For a system that sleeps most of the time (a telematics module or a BMS monitoring node), that 15 µA leakage is below the self-discharge of a coin cell, so the clock doesn't drain the backup battery during extended idle periods.
Package footprint and reflow compatibility
The 4-VDFN package measures 3.20 mm x 2.50 mm with a seated height of 0.90 mm — a compact footprint that fits tight enclosures and matches standard reflow profiles for surface-mount assembly. The small pad pitch means the PCB layout should use the manufacturer's recommended land pattern to avoid solder bridging.