This function is very usefull. Small example:
You are on the freq and calling CQ. Somebody calls you back, he is not tuned to your freqency but about 200 or 400Hz up/down. You use the RIT to correct the difference. You don't have to but on CW I have set pitch to my favourite tone freq and would like to have this tone also from station calling me. QSO is finished and you don't want to have this offset anymore. So if you have Clear RIT after saving QSO enabled, CQRLOG will clear the RIT automatically. 
73 Petr