Huggy welcome to the bbs.
The selespeed has a faster shift than a manual driver can manage.
You may think the manual is faster but it's what your brain thinks not the speed of the gearbox.
In a manual your brain is performing a function when you change gear, in the selespeed your brain is waiting for the change to take place so it feels longer.
In reality the selespeed will lift the power, operate the clutch, change gear, release the clutch and reapply the power in about a second normally. This is about as quick as most drivers could manage if really going for it never mind normal changing.
In fast mode above 5500rpm the whole thing happens in 300-400 milliseconds, show me a driver who could do that without crashing the gearbox.
It takes a while for the box to feel natural, you are not used to waiting for things to happen in a car as you are used doing them yourself which makes the changes feel slow initially. Autocar did a test on SMG type gearboxes and although the test showed the electronic sequential boxes were much quicker than the drivers doing the test most drivers said they felt they were changing gear faster themsevles.
From memory a good driver changing as fast as they could managed to do an entire change from the lifting of power to re-applying power in just under a second. A proffesional driver crashing the box and not lifting the power bouncing the revlimiter did the change in around half a second. This was all done with diagnotstic equipment not just a stopwatch.
The selespeed and the manual post the same 0-62mph times. The manual is slightly faster off the line (In the dry with good grip) but the selespeed makes the time up in the 1st to 2nd gear change. Also remember proffesional drivers did these times on a race track surface. The manual driver must get a perfectly balanced get away from the line and do a perfect gear change to match the selespeed.
On the road I believe the selespeed would have the edge.