Act 3, Scene 2: While Bassanio ponders over the three caskets, he makes a speech. What is the main point of this speech and his action at the conclusion of the speech?

Bassanio's main point in his speech is to look at the caskets, how they are made, and what the precious metals (or not) stand for. In the end, Bassanio chooses the lead casket based upon the knowledge that it, in itself, has no worth. In essence, this means that Bassanio is not materialistic.... he does not gravitate toward wealth or position, but rather, the woman he wants to marry.