Why foolish? Of course he is better on clay, but this is a weak challenger, where he could gain a lot of points with a semifinal?
I understand his thought process. He wants practice on hard-courts before (presumably) he goes to the States for the weeks leading up to the US Open.
The reason I think it's foolish, is he's going to be reacclimatising several times this summer. It's not ideal for building up form, which he badly needs. It's more than likely he'll be in the doldrums outside the top 100 next year.