Can you please slow down and read what's being written? Didn't even mention semantics.
One fictional example of what I mean: lets say I draw someone holding a purse. That would be a shape of their torso, with the purse overlaid. I could move those independently, and moving the purse would show the torso underneath.
However, using a png to svg, it would often just outline everything. So it's not a torso shape with a purse in front. It's a purse with a torso cut out around it, maybe even merged together as lots of individual shapes. If I were to delete the shapes making up the purse, it could be quite random what was left. Maybe some of the shapes did a double duty. Maybe it's a thousand small squares to make the purse. Maybe there is just a hole behind the purse etc.
So in the latter case, the svg isn't made up of logical elements, it's just made up of shape after shape after shape to mimic the pixels. But it's not usable as vector.
One fictional example of what I mean: lets say I draw someone holding a purse. That would be a shape of their torso, with the purse overlaid. I could move those independently, and moving the purse would show the torso underneath.
However, using a png to svg, it would often just outline everything. So it's not a torso shape with a purse in front. It's a purse with a torso cut out around it, maybe even merged together as lots of individual shapes. If I were to delete the shapes making up the purse, it could be quite random what was left. Maybe some of the shapes did a double duty. Maybe it's a thousand small squares to make the purse. Maybe there is just a hole behind the purse etc.
So in the latter case, the svg isn't made up of logical elements, it's just made up of shape after shape after shape to mimic the pixels. But it's not usable as vector.