Yes it seems to be that the rewards program is for US only. I enquired in the past about earning points while renting in Europe. Interesting thing is that at first Hertz did not know, had to wait a long while, and finally was told that I would not be able to earn point on my several thousand dollar rentals in Europe. And they did not feel sorry about it.

So you can not earn Hertz points with Hertz, nor redeem Hertz awards with Hertz. Just think if airlines did it this way, they would lose many customers...