It will be worth it in 1080p too, the Pro is not only for 4k tv owners.
Off the top of my head these games have confirmed 1080p specific modes:
Rise of the Tomb Raider
The Witness
Mass Effect Andromeda
Paragon
Probably more that I'm forgetting. Bottom line is that devs are catering to both 4k and 1080p owners. Even if a game only renders internally above 1080p, then that will give you automatic downsampling benefits.
Off the top of my head these games have confirmed 1080p specific modes:
Rise of the Tomb Raider
The Witness
Mass Effect Andromeda
Paragon
Probably more that I'm forgetting. Bottom line is that devs are catering to both 4k and 1080p owners. Even if a game only renders internally above 1080p, then that will give you automatic downsampling benefits.