It used to be the case that the serious gamers played any of a dozen different tabletop RPG systems — Dungeons & Dragons and its knock-offs, Champions, Cyberpunk 2020, Shadowrun etc. Serious players would spend anywhere from four to twelve hours at a time, maybe several times a week. But for all that, you didn't really get a lot done in one of those marathon gaming sessions. Sometimes, you might manage to get from one town to the next, or maybe only part way there, or you might maybe clear a couple of rooms of the current adventure "dungeon" that you'd been working on for the last couple of months. But you'd seldom accomplish more.
( Why? )
And when the mechanics of your game, for no good and necessary reason, obstruct the play of your game and force the player to break his or her immersion in the game to deal with mere mechanics, then you have failed at game design. The game mechanics are, quite simply, necessary underlying structure for the workings of the game; and that is all they are. They are not the purpose of the game. The gameplay is the purpose of the game.