Lots of people have tried them, I guess you didn't read the known issues part as well:
[SLI, Batman: Arkham Knights] With a 4K display, a TDR occurs after the in-game
resolution is toggled and the application is exited. [200116725]
[SLI, Batman: Arkham Knights] Heavy flickering occurs in game after Alt+Tab if SLI is
enabled. [200116723]
[SLI, Batman: Arkham Knights] Severe stuttering seen, especially in indoor scenes,
when the game is running at 4K resolution and NVIDIA Gameworks settings are
turned on. [200116722]
[SLI, Batman: Arkham Knights] Random flickering occurs in the game if SLI is
enabled. [200116717]
[GM206, SLI, Batman: Arkham Knights] Stuttering occurs and performance drops
after shadow quality settings are toggled. [200116694]
[GK180, SLI, Batman: Arkham Knights] When SLI is enabled, a crash points to ntdll.dll shortly after the game is exited. [200116717]