Why destroy Laketown's bridge?

[Sauron the White]

A picture says a thousand words.
Thank you to davem for supplying that drawing of Laketown. It does two things to reinforce my point:
1- the bridge is no flimsy thing supported by ropes. It is on strong and thick pillars. And like davem says, it looks like it is not easily destroyed without yet another litany of assumptions about many thing not visibe in the picture or written about in the text.
2- the area of the docks between the water and the buildings is indeed much wider than the actual bridge itself. Given the thinness of Smaug (again based on the other JRRT painting) he could have just as easilly landed on any of that docking space as opposed to that bridge. Which is what I have been saying from the very beginning. Smaug did not need the bridge if his intention was to land and go house to house.

I do think that if this passage had been written for LOTR, it would have been longer, more fully developed and the detail much crisper and clearer. JRRT would have explained what Smaugs intentions were, and perhaps explained why it ws necessary to thrown down and destroy the bridge. JRRT was such a superb writer that I have no doubt it would have made perfect sense.

Having said that, THE HOBBIT was written on a far different level and that type of explaination and detail was simply not there. As a result, we get a rather confusing couple of lines that are open to various different meanings.