The patch dropped Wednesday. its been 3 days since then and EVERYONE is playing these champs with this item. People who normally would play champs that use it are playing them. Very few people know how the synergy works, when to get it, and how to time it. People said the same thing about Gnar and he turned out to be a big hit later on. Have you seen illaoi yet? No, because people are again getting use to her. Time is needed for all these changes because they are brand new and change a lot about the game.
It could fizzle out and be just a throwaway item, a luxury item, or broken once people learn to synergize it with items and champs. No one knows how its going to change things. Clearly its not stupid broken enough so any one can just buy and win, but it doesn't mean it won't be too strong on these champs.