"Power Giant" works well in a "Scrap" Deck, due to the fact that major "Scrap" cards utilize the Graveyard for their effects and also because it itself is excellent fodder for Synchro Summons.
Discard "Road Synchron" to Special Summon this card and make it a level 2 monster. Then, Normal Summon "Synchron Explorer" and use it's effect to Special Summon "Road Synchron" and then Synchro Summon "Road Warrior" ("Power Giant" (2) + "Road Synchron" (4) + "[Synchron Explorer" (2) = "Road Warrior" (8)).
By discarding a Level 3 Monster then summoning another, this card can be used for an easy Xyz Summon in a deck that utilizes many Level 3 monsters.
Send "Lightserpent" as this card's Summoning cost to gather the materials for a Rank 3 Xyz Monster without using your Normal Summon for the turn.
Discard "Glow-Up Bulb" to Special Summon this card and make it a level 5 monster. Then, Special Summon "Glow-Up Bulb", to Synchro Summon for "Naturia Barkion". And you will still have a Normal Summon for that turn.