Kraken launches its cryptocurrency exchange app to the U.S., putting it in direct competition wit Coinbase (COIN).As of today, the app will allow users in the U.S. to buy and sell more than 50 cryptocurrency tokens through their bank accounts using their mobile phones."This consumer app is our first major foray into supporting wider consumer adoption in a much more simplified, easy-to-use interface," Kraken Chief Product Officer Jeremy Welch told CNBC in an interview.The company said the app offers low fees and touts it as "perfect for beginners," providing tools for learning about bitcoin and other crypto.In April, before a cryptocurrency selloff in May, CEO Jesse Powell told CNBC that Kraken was considering going public through a direct listing.In March, the SEC warned that online trading platforms for digital assets must be registered.