[mirker]

Tin is normal (and also the reason the loaf is rectangular with a mushroom top rather than round): https://www.kingarthurbaking.com/recipes/classic-sandwich-br...

For batter vs. dough: yes, they are not the same, but adding any fat to dough inhibits glutten (e.g., https://cooking.stackexchange.com/questions/36267/how-does-f...), which is why sandwich bread is soft and spongy. It may not pour, but neither does muffin batter or brownies, for example. My point is there is a whole spectrum for gluten formation.

Compare the cake recipe https://www.kingarthurbaking.com/recipes/classic-birthday-ca... to the bread recipe above. The main difference is that butter is added along with eggs, and the leavening is different. Artisan bread only has the 4 ingredients, sandwich bread adds sugar, milk, and oil, and cake changes leavening and adds eggs/butter. As you go up the spectrum, you are intentionally avoiding strong gluten development, resulting in smaller holes and softer texture. See challah bread for another data point of bread with eggs+oil https://www.kingarthurbaking.com/recipes/classic-challah-rec.... You can also make the gluten weak by using something like 100% rye, which has to be baked in the same tin (though that would have a harder crust).

[djur]

I have made that exact King Arthur sandwich bread recipe and it doesn't do anything like "pour". Loaf pans are used for sandwich bread to get more lift and a more sandwich-friendly shape, but there is far more gluten development than any cake batter. You can use that same recipe to make rolls, for instance, and they bake up just fine.

The cake recipe has a 2:3 ratio of flour to sugar, while the bread recipe has a 14:1 ratio. It also has a 2:1 ratio of flour to fat, with the bread being 6:1. The cake also has a much higher hydration ratio, more milk, eggs, and a completely different mixing process.

Really not "essentially" the same thing at all.