They toyed with the idea of using Ethereum or EOS and then settled on WAX, which is an EOS clone that is especially geared for trading items for video games. Thought its been around for a couple years now, WAX hasn't really brought any video game publishers on board, and the Topps launch of the GPK series is by far their biggest event to date.
I've created
a thread about Decentraland and its ERC721 non-fungible tokens a few months ago. The first problem I noticed was that the Ethereum network was very inadequate and costly for a game. I had to pay around ~10 cent transfer fee for each transaction I made in the game even if I adjust 1gwei as a transfer fee. For this reason, Topps Company must have been preferred the WAX blockchain instead of the Ethereum network. As you said; who missed the boat have to learn how to buy WAX to get those cards, and this is encouraging new people who don't know cryptos to learn something about this world. Games, cards or similar things built on the blockchain will have a positive impact on the rise of the cryptocurrency market in the long term.