I personally go for piracy as a tool to see how much a game is worth in it's entirety to me personally. Businesses are quite articulate about trying to milk as much money out of us as possible, and demos either last 2 hours, which is not enough to form any kind of opinion, and some games are designed to tapper off around that time.
Other reasons include being from a country which isn't a first world country. Recently got a good job and am making 4$ an hour. My paycheck used to be 300$ a month before this, and on such economies games aren't affordable at their 60$ prices, plus as a kid I couldn't even buy stuff and father used to buy burnt copies of games, so I suppose I was a pirate before I knew what that meant.
All of this makes it so when I find a game and play through it I decide how much I'll pay for it. Eg. Undertale I bought 3 copies after finishing it, DMC 5 and RE 2 remake I bought for full prices after finishing, Witcher 3 I haven't played, but still bought for full price. Some games I'll play, but decide not to give the full value, but instead wait for a sale, eg. new Deus Ex. Some games I'll pirate and decide not to buy in the end (Lost Sphear comes to mind).
Basically I take the power and decision about how exactly and how much to support someone with my wallet into my own hands.
In this particular case piracy even gets you a huge benefit of not going through the Epic launcher, and since it still gets them a sale the argument of piracy losing out sales can't be applied.
Tl;dr. The way I see it pirating this game is literally a win - win situation as it stands now, for all parties involved. They get the money they would've gotten anyway, only this time from a corporate entity instead of a person, you get to play the game on release, instead of the 1 year delay, and you have less chance of infecting your computer with malicious crap by pirating and not using the Epic platform.