Unless, y'know, you want to participate in multiplayer
I had assumed EA Access would require an active Xbox Live Gold membership to use given the way these things usually go but it turns out that's not the case. When the subscription service launches later this summer, it'll just be $4.99 per month or $29.99 per year -- no extra Gold charge. That said, if you want to play games online, you will need a Gold account.
Another thing I learned from the FAQ is that the program's "pre-release trials" aren't merely going to be early demos. "When you play a trial through EA Access, you are playing the real game for a limited time, five days before the release date," says EA.
"And if you buy the game once it releases, you don't need to download or install anything; you can just pick up where you left off and keep playing ... Each game is different, so each game's trial will be, too. In some titles you'll be able to play one of the game's modes for a limited time, while other times you can jump right into the full game."
Better than I thought initially, then. The service sounds decent enough.
FAQ [EA Access]