Can't hurt to register for this.
From the page:
Whether it’s business or leisure, with Hertz you’ll always find your way. Enrol into the Hertz Gold Plus Rewards® loyalty programme now and take advantage of your special Hertz privileges, exclusive to you. With more cars and a wider choice at over 8,500 locations across 150 countries, Hertz is your perfect partner for the journey ahead.
As a Cardmember enrolled into the Hertz Gold Plus Rewards ® loyalty programme, you will enjoy a range of exclusive benefits* at participating locations across the world:
• Value: 10% discount off standard rates.
• Comfort: One car class upgrade (applicable to standard vehicles only and valid for rentals of five consecutive days or more, subject to availability)
• Choice: Fee-waived additional driver
Note: You are required to add your credit card to your account as part of the sign in process.