In most rigging tutorials they setup the bones like this. But there's no way to swing the hips properly without special "control" bones.
Why not place the bone like this?
This makes sense to me, but every professional tutorial I find does it like the first image. Even the built in rigify metarigs are like that. There must be something I'm missing. Is it wrong anatomy?
Either way you're showing is fine. The weights are the same, and all you're doing is changing the center of rotation of the root.
But control bones aren't special, and for most riggers, they're not really optional either. So these tutorials are showing you how to place deforming bones, expecting you to create control bones as well.
It is very useful to have a bone at the center of gravity of models. This is the point about which models will, mostly, rotate. If we swing our hips, we're rotating about our center of gravity. But the center of gravity isn't at the level of either end of your spine0. Spine0's position was chosen for its effects on autoweights, not for its relation to what people's bodies rotate about. Neither end is the right center of rotation. After this first step, of getting good deforming bones and good weights for them, we might make a non-deforming Center bone, and then parent spine0 to it:
Once we have that, it doesn't matter whether spine0 points up or down, because we're not rotating spine0 anyways, we're rotating CoG.
If we do that, are there any reasons to prefer spine0 pointing towards, rather than away from, spine1? Yes, if we want to set up bendy bones for our spine, or if we want to use IK (spline or regular), the orientation shown is easier to set up. Otherwise? No, it really doesn't matter.
However, you should absolutely feel free to create your rig however you'd like! There is no right answer about hierarchy questions like these. Different designs support different animations and different animators, that's all. Tutorials are showing you one way to build an armature, which is a good first way, a good way to get started, but you're fully expected to go your own way afterwards as you get a feel for how you like to rig and for how you (or your team) like to animate.
Because it was root bone, like control center for armature. If you flip it the upper bone will be root done instead which is really hard to work with.
Rotate default Human(Meta-Rig) around X axis.
Rotate your design around X axis.
To achieve the same result have to select all bone or go back to Object Mode. Imaging, if you want animate your character to jump and flip, especially when you want to export it to game engine, this is nightmare.
