I haven't played a FIFA game in probably 20 years so please excuse my potentially uninformed question. Do loot boxes improve the play experience of the game in any meaningful way?
EA will release packs that contain star players with much higher ratings. In order to get these higher rated players on your team, you can either grind the game for several hours a day or pay to open some packs that might have the high rated players inside.
The player(s) you receive when you open the box is random and not known before you open the box.