Goods: unlike closed water cooling that can spring leaks, you're creating one big leak here So the good is that it won't damage your components initially. Over time they may become contaminated with conductor and semi-conductor materials, possibly causing your board to short or hang. Though due to the properties of the oil, this is less likely to occur.Is there anything good with submerging your computer in mineral oil? Sounds weird to me
The fan acts like a fountain in the middle of a lake, it's not there to look at (just for aesthetic value), it's there to move the algae. In the computer's case, it's there to move/circulate the oil to help cool it down, or at least disperse the hot oil and hopefully have it replaced by cooler oil.I would think it is pretty useless and why would you need to keep the fan if it is submerged in the oil?