It's not about the shift itself. It's about how long it takes from the input of my foot, to the power at the wheels.

A great example is spontaneous overtaking. For my taste, it takes way too long for the AT to shift down, while with MT I can shift down before I press the accelerator.

That, and getting stuck in snow or dirt. With MT you can also sort of sway yourself out of a problem.

Anyway, preference, etc. Both has pros and cons, it's up to the driver to decide what pros matter to them.