If I was to guess Splinterlands is a bid to make a game like Hearthstone/Magic the Gathering and turn it to a blockchain game. In the future they are looking to add land, resources, keeps and a map to flesh out the world of Splinterlands. They have also mentioned trying to do a Player vs Environment where you can have a summoner travel teh lands doing battles for rewards. Add in books, comics and more and the Splinterlands team does have a lot they want to accomplish.
Then add in the competitive aspect with their goal to bring in competitive gaming teams and big prizes.
Will it ever be commonly known? Honestly I doubt it, but if it does that will be really cool and I'm certainly hoping for it :)
RE: Does Splinterlands have mainstream appeal?