Probably no good reason to be honest. But some people are willing to withstand increased NVH for a little less drivetrain movement. Also, I would like to believe that my poly engine mounts and UUC black tranny mounts w/ enforcer cups will last longer and be a lower maintenance item. Only time will tell.
Honestly, staying OEM is not a bad idea. Likely a pretty good idea.
2013 F30 328i - Melbourne Red
2011 E90 M3 - Monte Carlo Blue
2004 E46 M3 - Imola red