What's bad about them?
Really? I mean the oil lasts almost indefinitely, in sooo many cases it outlasts the entire car. Don't be a cheap ass on this one it may come back to haunt you later. As long as it isn't leaking it will stay in there. The bigger question is why is your level so low in the first place?
Jeff
The motor oil becomes thick and sticky. Supercharger oil (which is synthetic) is very then even when cold. It is closer to a spindle oil used on high end CNC milling machines. Maybe closer to other stuff but I work with a lot of different CNC equipment and it's a similar application, gears ball bearings but no clutches.
The front pulley ball bearing only gets lubricated by the atomized oil that has to pass through the coupler ball bearings. So we are counting on the oil bearing atomized.
The front bearing is normally the first bearing to fail with its high side load from the belt tension and its poor lubrication. Note that the lubrication also removes heat from the bearings which prolongs life.