Wondering the same thing...
I think not.
Apparently the McFaul had 55 tons of humanitarian supplies on board. To go directly to Poti would have required a significant effort to make sure the Port had not been mined or sabotaged so the vessel could get to dock and unload...aftyer which the supplies would have had to contend with the Russian force blocking the interest by highway to the Port.
This way they unload all of that humanirarian effort, which the Georgians need, and avoid the longer wait and the potential for the supplies being interdicted by the Russians.
Apparently the force outside of Poti is relatively small in any case, and bypassing them not only gets the supplies to the Georgians, it renders the Russians there irrelevant to opposing the humanitarian effort.
My guess is that it will not be too long before they leave...and it is not out of the question that the US will help in making sure that happens once more ships arrive and their humanitarian supplies are offloaded.