Why did the RAAF procure the F/A-18 despite being purpose-built for carriers?
Two reasons:

The airplane is extremely versatile, while having adequate performance, and is a good choice when a small airforce needs a do-everything airplane to replace multiple types.

Being designed for carriers, it's overbuilt for normal land operations in many key areas, which means a longer airframe structural life in its much easier life landing on runways.  For an air force with a limited budget and the need to run the airplane a long time, it's worth giving up some of the speed/payload/range that was sacrificed by the structural needs of carrier ops.