What happens when you dorsiflex (toes toward knee) the front foot in splits? Some seem to think that it stretches your hamstrings more, because the action makes the hamstring region feel more intense.
It's not stretching your hamstrings.
This action stretches your calf, which you don't need to do in splits. Hamstrings insert at the knee, not the ankle. So movement at the ankle can't affect the hamstrings.
The reason your hamstring region feels more intense when you flex the foot in splits is that you're pulling on the sciatic nerve. In my personal opinion, this is unnecessary and I don't recommend it. However, some argue that flexing the foot in this way can loosen a chain of fascia along the back of the leg. I can't confirm or deny this, but if you know about it, feel free to message me or leave a comment.
Nerve glides is an interesting topic as well. Some say that it is useful to point and flex the foot to loosen up the nerve for the stretch. I have heard that nerve glides work better with both ends of the nerve on slack. That means that when you dorsiflex, the knee bends, when you point the foot, the knee straightens. If you're just in splits flexing and pointing your foot, in my experience it feels pretty intense, and not in a good way. I have noticed that the more weight I have over my leg while the foot is flexed, the worse it feels. When I sit up and arch back in splits, it will be less of an issue but I still wouldn't ever do it, I have not found any value in it personally.
My opinion on aesthetics is that a pointed foot is prefered in most cases. However, not everybody agrees with that. Some like to see the toes drawing toward the body. This seems more common in yoga.
I believe Dorsiflexion is great as an aesthetic choice when chosen purposefully and when there is no weight over the leg while the hamstrings are being stretched.