If you’re familiar with Magic, imagine that with a better resource system and with your turn and your opponents turn squashed into one round, in which every action you take passes priority. I bought two of the base sets when they were on clearance at Target, and the kids loved it, so I bought ten boosters of each of three sets.
That’s not a good way to do things. I’m particularly vexed that one of the sets introduced a few vehicles and lots of cards to support them. So, if you’re going to blind-buy, get a bunch of a single set. A better option might be one of the fixed starter packs to supplement one (or probably two) cores.
Matt Thrower wrote a great piece about it, which is what made me decide it was promising for casual play: https://therewillbe.games/articles-boardgame-reviews/5745-star-wars-destiny-review
I think it’s a pretty neat game, but my kids have gotten on a big social deduction kick, so they always want werewolf or The Resistance: Avalon, and I haven’t played as much as I’d like.