Possibly a PR stunt.
No way will he get 1,000 poor chess player stumping up $1,000.
The Exchange French still has bite if one player is up for it.
Kasparov played it v Korchnoi when needing a win - and he got it.
But that is Kasparov.
On here I have the Exchange French 10,281 times.
White Wins 4,016
Draws 1441 ( 15% )
Black Wins 4,824
The more Black wins are possibly due to Watson's off the cuff remark
that after 3...exd5
White is in Zugzwang.
What ever plan White adopts Black has a good antidote.