Why hold'claim Osgiliath?

[William Cloud Hicklin]

It was hardly giving up some secret to attack Osgiliath in June- Osgiliath was almost necessarily the main focus. Any campaign against MT from Morgul would necessarily rely on the Road and its causeway, which meant Osgiliath.

Moreover, Sauron's plan in June was to seize the Bridge, not to have it destroyed- which would indeed have been an immense prize, and which he would have gained but for Boromir and Faramir.

Tolkien himself admitted that the Nazgul/water business was 'hard to sustain'- but the basic argument, that the assault provided cover and disinformazia for the RW's hunt for the Ring, still holds up. Nor is there anything at all wrong with a reconnaisance in force to probe the enemy defenses.