The key advantage of all-optical regeneration is the power efficiency provided by the device and simpler integration into an optical network.
Cost efficiency has led to OEO repeaters being largely replaced in long-haul systems by optical amplifiers since one (broadband) amplifier can be used for many wavelengths in a Wavelength Division Multiplexing (WDM) system.
Note that this class of device is sometimes called "Optical Amplifier Repeater".
[2] Due to the high data rates that can be achieved with optical systems, OEO repeaters are expensive to implement as electronics to handle those high data rates are expensive and difficult to construct.
An amplifier does not provide the regeneration ability of a repeater, but loss, rather than distortion is generally the limiting factor in the design of an optical communications system.