Yeah it's just for publicity no doubt. Suing the bank doesn't really raise an eyebrow. But sue for $1,784,000,000,000,000,000,000,000 and all of a sudden everybody in the world knows how displeased you are with your bank.
There should be a secret society that looks out for things like this.
Working on the basis of "common sense" (which is wholly lacking in the world) they should spot these things and take ALL but $1m from the person involved.
Having or earning money is one thing, being a prat with nothing better to do is another.