This game is not as complex and deep as MtG, but still it requires a lot more of strategic thinking and deck-building skills than HS. At the same time, a game of Eternal can usually be finished within 10 minutes.
Draft allows you to keep the cards you pick and earn some extra rewards. Unique mechanics allow signalling and signal-reading in draft while still allowing you to draft on your own time (no waiting for pod or passing).
Best played on a PC or a tablet. Playing on a phone can be difficult as it's a direct port from PC so text and images can be tiny. Not a problem if you're familiar with the game, but new players it will be frustrating.