I opine that the flight manual statement "Land immediately" should be ammended to also say "... and crash if you have to", if that's the reality of the situation. Let's call it what is is!
While this has been previously addressed, I think the idea of "land" immediately is to avoid "crash" at a point in time later.
Ditch = land on the water in a controlled manner, rather than "crash" into the water.
Cheers.