Does practicing really work like this?

[swagmaster420x]

If u play smth five times right and five times wrong, you practiced playing it wrong as much as you've practiced it right so it cancels out in your muscle memory and you've gotten nowhere.

Or if you have greater intent, the five right times will be imprinted better in your mind/muscle memory, and you will have gotten somewhere. If this is true, then depending on how much intent you have while practicing you could either be incredibly efficient or wasting all your practice time

[faulty_damper]

If u play smth five times right and five times wrong, you practiced playing it wrong as much as you've practiced it right so it cancels out in your muscle memory and you've gotten nowhere.

False.  You actually learned both ways, but since you only repeated it five times, it's unlikely to form a stable, precise memory.

Or if you have greater intent, the five right times will be imprinted better in your mind/muscle memory, and you will have gotten somewhere. If this is true, then depending on how much intent you have while practicing you could either be incredibly efficient or wasting all your practice time

Also false.  You still learn both ways.  But by "greater intent", do you mean greater focus?  If you mean focus, then maybe because you are activating multiple areas of the brain for this task while suppressing others which are not necessary for the task.