You are only missing the fact that you are asking a seller to point out the downsides of his product.... how likely did you think that was?
Even if the above has an element of truth, what about excess pressure, excess temperature, oil degradation, etc.?
Always read between the lines
and mainly research user experience and especially those who have used it for some time. Appears that there are not many complaints, but I have not researched too much personally as it is not (yet) on my to-do.