actually the semi auto is a term....
so dont matter if the transmission uses clutch or torque converter...
its just another term, like tip-tronic... marketing ma....
throw in some bombastic word and people will think... wahhhhhh so high tech...
u seen the drag video where a golf GTI manual vs golf GTI with DSG, both driven by Keiichi Tsuchiya...
even with his shifting skills, he can't get the manual GTI to beat the DSG equipped GTI..

but that is straight line la...
video for your reference..
Drift King Test Golf GTI (DSG vs 6spd Manual) - YouTube
so it depends,
humans can never shift faster then what technology like DSG/Dual-clutch can do...
humans might be able to match the shift speed of conventional torque converter gearbox...
where as in tracks where there is turns involved, a pure manual will still be better as u can have full control of the gear u wanted to be in, (example, u can force downshift even if u know the rev is still too high, u can bounce against the rev cut when u are in "no-man's land" etc) as compared to a DSG/Auto because the DSG/Auto TCU/software is programmed to upshift once u hit certain rev's etc to protect the gearbox...
of course u can remap the software but this comes at a risk of saying early good-bye to the gearbox