Some media converter models have an LFP switch. It is needed so that when the optics disappear the copper port is turned off and vice versa, if there is no link on the copper port, the optical one will also be turned off.
The LFP function, for example, is useful in cases when the media converter is connected through a copper port to the managed switch and when the optical link disappears, the copper port turns off, which can be seen on the switch.
Otherwise, if the LFP is disabled and there is no link between the converters, the link with zero incoming traffic will remain on the switch port, which will not be clear whether there is no link between the converters or simply nothing is connected to the media converter from the user side.