I don't think OLCI affect much on your upgrade chance.
It might help if you notify them about your check in time so they theoretically assign you a suite that was vacated on 4pm by members if you plan to arrive late,
However, in my experience, using OLCI doesn't make my check in faster on most occasion as the front desk agent still check the room inventory on arrival.
On some rare instances they do have key and everything premade and waiting for my arrival. In this case, I believe you could still ask if there is any available room suite upgrade anyway.

As for upgrade chance, I guess it might help if the hotel premade the key and assign the room on OLCI, however if the hotel assign the room on arrival regardless of OLCI then OLCI won't have much effect.
Similarly, if you already pre upgraded, doing OLCI might help "lock" the room for you, but then again hotel can just reassign you to other room/suite if you haven't got the key.