I know I can turn it on and also use the OptionTab but I was wondering why they would use that as the default in the first place. There was an article about it from 2014 but has been updated over time.
Coming from Windows it did catch me off guard especially since I leverage the keyboard for faster data entry since I don't have to do input context switch between keyboard and the mouse.
Even if you say if "normal" sighted there's no need to use the keyboard and they tend to use the mouse, why would they still allow Tab to focus between fields?
The only thing I can think of is that they may just not want to change a decision they made a while back until people stop buying their products. Much like having the bumps on the D and K keys rather than F and J like most other keyboards on the planet.