Unless the quantity is less than 5, tap to increase doesn't make sense.

Also, the slider wouldn't work in case you are trying to choose from an even average sized list on "min" or "max" side. There are only so many pixels in portrait mode and my big thumb - how can you expect it to be so precise. While in case of the dropdown in almost 2 scrolls i can get to the exact number by varying the speed of scroll, like binary search.

Some of the points are correct though, i don't see many people making those mistakes.

-In this specific context, I would think the large majority of people are flying with a party of 3 or less. So it should be less clicks for most.

-Thinking more broadly, just because you may need to click the stepper more I wouldnt necessarily say its more complex. The user should immediately understand that each increment is equivalent.

When I click a dropdown, there is a lot of thinking required. I can't see the options before clicking it. Maybe it starts at "0", maybe it starts at "1". Maybe its all text choices and I have to read them all in that tiny window. Maybe I over-spin. There is actually a good amount of dexterity involved.

Even if I have to hit the stepper 10 times, a user can do that incredibly quickly and without having to actively use their brain.

[0] I've always heard them called "spinners".

[1] You could probably emulate this with something like a two-fingered horizontal swipe starting in the widget

1 tap to select the input field

1 swipe to move the desired item into view (I guess this is a tap)

1 tap to select the desired item

1 tap to move on to the next field using the arrow utilities, or one tap for "Done"

That's four.