Riding toe-down/pointed can make you feel more powerful in the short term. I can't explain why - foot position shouldnt matter since your power is coming from your quads/glutes, but a lot of people swear to the phenomenon. The thing is, don't do it! By keeping your Achilles tendon tight, you will make injuring it much more likely. Achilles tendon injuries can take a looooong time to heal, and may bother you for years afterward.