I still don't find sufficient reason to play Hydreigon in a Darkrai list without playing Max Potion. You state that your opponents will commit to the game in a way inadequate to how one ought to play against a Darkrai Hydreigon deck. However, I can only think of the truth of the proverb: "It's better to have it and not need it than to need it and not have it." In my mind, a Terrakion player, amongst others, would be glad to indirectly achieve the effect of Tool Scrapper by not needing to play the card in order to maintain a field devoid of Eviolited Darkrai. They would be even more glad to be granted the opportunity to set up knock-outs on opposing Pokemon unhindered from Max Potion. Even more so, Crushing Hammer as an offensive play slows and is slowed by the presense of a stage two Hydreigon. In my mind, these situations do not justify playing Hydreigon for the sole purpose of moving energy among attackers. Not every deck plays Tool Scrapper, and it's not guarenteed to be availale at all times of a game, meaning Eviolite can protect your Darkrai from a knock-out. Likewise, a majority of decks cannot do better than to knock out Darkrai in two attacks, and even so, most decks do often set up knock-outs on opposing Pokemon, a situation that Max Potion can take advantage of to effectively undo your opponent's attack. Is it still not worth playing these cards?