At the end of the day SMG is just not a 6MT, and I would dare any SMG driver to hit a drift as fast and as long as I can in my 6MT. Your exactly right, the fun factor is not there. The SMG is far superior to any human shifting and even many world class driver can not down shift as quickly and accurately as the SMG, but the SMG is also considered one more fail point on the vehicle. The 6MT will hold more power as previously stated, and has a less likely chance of failure. Thats where it gets slippery. do you get the SMG for the track car because of its abilities, but risk the chance of failure and tuning complications. Or do you take the 6MT and lose the quick shift and downshifting capabilities for a stronger more reliable system?
I have seen pro teams go both ways with great results. personally i wouldnt be able to decide. I have never owned an SMG but i have driven them and let me tell you something. Once you master the left-foot-braking technique, holy crap your untouchable on a track, for the most part. being able to upshift, downshift, and brake all while your at full throttle...c'mon no standard gear box can compete.. all that being said.
I wouldnt trade my 6MT for anything....