We had three voters. That's not much. And the votes are equally divided: one vote for each option.
Personally, I firmly believe that it is best for beginners to shoot in manual mode exclusively as it is the only way to truly learn about light and how to properly expose photos. After all, photography is capturing light and how will new photographers learn about that if the camera makes the changes for them? Sometimes the change in light is subtle. But when shooting in manual mode you will see it. You will miss it in Tv or Av mode as the camera immediately compensates.
I think that once you know how to take a good photograph yourself, in terms of exposure, it's fine to use whatever mode you want: one of the semi-automated modes or even the green box if that suits you for a particular situation. But to use the Green box or P or Av or whatever because you don't know how to properly expose your shots, in my opinion, is a bad idea as it will teach you nothing.
And there's also what Dave touched upon: how the three variables on the exposure triangle affect the resulting image differently. I tried using auto ISO on my 1D4 once. I was done with that after 10 minutes because the camera made choices that I never would. I haven't tried it since and maybe it's much improved. I know most people use it and love it. I guess I'm a dinosaur. There is one thing that is automated on my R6m2 and R5m2 and that is when I zoom in or out, the ISO speed is automatically adapted to the new aperture so the exposure stays the same. Very handy.