This combination of low Rds(on) and high current capability makes it suited for low-voltage, high-current switching applications such as power supply secondary-side rectification, DC-DC converters, motor drives, and battery management systems where board space is not the primary constraint.
The 80 A continuous drain current is a package-limited rating at case temperature — in a real design, the actual current is derated by the junction-to-case thermal resistance and the ambient conditions. The 3.3 mOhm maximum Rds(on) at 10 V gate drive is the headline figure for conduction loss; at 40 A the dissipation is roughly 5.3 W, which the TO-220 package can handle with adequate heatsinking. The gate charge of 40 nC at 4.5 V is moderate — the driver needs to supply that charge each switching cycle, so at 100 kHz the average gate drive current is about 4 mA, which is within the capability of most MOSFET drivers.
Lifecycle reality — obsolete, sourced to order
For new designs, a pin-compatible alternative from the same or another manufacturer should be evaluated. This is a typical situation for a mature, end-of-life power MOSFET: the buyer should expect to work with a broker or surplus channel for the remaining service life of the product.