Question about DFR1026 DC-DC Charge Discharge Integrated Module (5V/2A)

In the description of the DFR1026 there is a line which says “When charging and discharging at the same time, please enable input and output to keep a balance, thus extending module service life.”

Can someone elaborate on this. I don't understand what it means. Does this mean one must press the key button to enable the output when a power source and load is connected? Under what condition is the module service life reduced? Isn't the input enabled as soon as power is connected?

Thanks