Effect cannot be activated when destroyed by effect/flip-negating monsters.
Gives your opponents monster cards, if there are any from the 3 draws.
Hiro's Shadow Scout can be paired up with Warm Worm to mill your opponent's deck. Other support cards such as Conscription and Cup of Ace can also be considered. Ancient Telescope can be used when you want your opponent to discard some specific spell cards.
Your opponent draws cards / Reveals your opponent's hand / Your opponent discards
it is not cheat, more like the requirement of the card to be activated. Cup of Ace let you/opponent draw 2 cards, thus the pre-requirement to activate it is both of u has to have at least 2 cards in deck.
Hiro, on the other hand, the require activate the effect is by flip it. The consequence, opp has to draw 3 cards. If he cant, he lose.