I mean the weird side-games or modes that reinvent the core mechanics of the game. Things like Mario Party 3's Duel Mode, which, if memory serves, shared at least a handful of minigames with the core game, but was, for the most part, its own game; or Final Fantasy X's Blitzball, which is the best underwater sport and sport management game I have ever played; or even Pazaak, KotOR's custom-decked Blackjack, all serve a very important purpose: to be fun when the regular game becomes tedious.
It's almost a trick. Instead of revving up another game when the player gets bored, they'll just spend a few minutes racing chocobos or gambling before getting back to saving the world or universe or whatever they were doing. Including a minigame is a wonderful move for the player, but it means making another game for the developer, which isn't exactly what you want to have to do if time or work hours are an issue.
Then there's Sid Meier's Pirates. Which is all minigames, but they're all important enough to the world that they inhabit that they aren't simple distractions. It's a game that actually has a wide array of things the player can do.
And that's the goal for FlyShootTrade. But without minigames, because damn. Those things take a mountain of extra time.