The new AppleTV remotes (Siri remote second generation) still have an IR transmitter, so the statements above about "penny pinching" or the remote "not having IR" are inaccurate.

As OP noticed, the ATV remote will default to CEC control if CEC is enabled on the TV.

Personally I think that Samsung should put the control over Art Mode in their TV settings (eg a "Power Off turns on Art Mode" setting) rather than stacking codes on the same button of the factory remote. Using it with any control system similarly requires switching between custom TV control profiles (drivers, modules) that substitutes the Art Mode commands for the Power Off ones, or vice versa. As it is I have to find out at install if the client wants Art Mode instead of Off, or the other way around; and then they're locked into that decision until a programming change is made.