On X-Box and PS3, you get points for doing so. Possibly just rep, or points used for a game in the future.
Pilotwings 64 Achievements
Engine Block: Get Gold on all Gyrocopter Levels
Gust Rider: Get Gold on all Hang Glider Levels
Rocketeer: Get Gold on all Rocket Belt Levels
Marksman: Get Gold on all Cannonball Levels
Jumbler: Get Gold on all Jumble Hopper Levels
Sky Surfing: Get Gold on all Skydiving Levels
Gilded Wings: Find all the Hidden Stars
The Real McCoy: Defeat Mecha Hawk as Hawk
Sculptor: Shoot Mario's Head in Little States
F-Zero X Achievements:
Royal Flush: Get Gold Medal on All Face Value Cups on all difficulties except Master
Wild Card: Get Gold Medal on X Cup on all difficulties except Master
Master of Racing: Get Gold Medal on All Cups on Master Difficulty
Grim Reaper: Complete Death Race
True Reaper: Complete Death Race with all machines
Speedy Reaper: Complete Death Race within 120 seconds
Sonic Boom: Break 1223 km
Zelda Ocarina of Time Achievements: (More Feasible ones)
Magician: Find all the Great Fairies
Supreme Smith: Get the Biggoron's Sword
Thirsty?: Find all Bottles
Legendary Fish: Catch the Hylian Loach as Adult Link
Bald as a Bean: Steal the Fisherman's Hat as Adult Link
Tip-Top Shape: Find all Heart Pieces
Pilotwings 64 Achievements
Engine Block: Get Gold on all Gyrocopter Levels
Gust Rider: Get Gold on all Hang Glider Levels
Rocketeer: Get Gold on all Rocket Belt Levels
Marksman: Get Gold on all Cannonball Levels
Jumbler: Get Gold on all Jumble Hopper Levels
Sky Surfing: Get Gold on all Skydiving Levels
Gilded Wings: Find all the Hidden Stars
The Real McCoy: Defeat Mecha Hawk as Hawk
Sculptor: Shoot Mario's Head in Little States
F-Zero X Achievements:
Royal Flush: Get Gold Medal on All Face Value Cups on all difficulties except Master
Wild Card: Get Gold Medal on X Cup on all difficulties except Master
Master of Racing: Get Gold Medal on All Cups on Master Difficulty
Grim Reaper: Complete Death Race
True Reaper: Complete Death Race with all machines
Speedy Reaper: Complete Death Race within 120 seconds
Sonic Boom: Break 1223 km
Zelda Ocarina of Time Achievements: (More Feasible ones)
Magician: Find all the Great Fairies
Supreme Smith: Get the Biggoron's Sword
Thirsty?: Find all Bottles
Legendary Fish: Catch the Hylian Loach as Adult Link
Bald as a Bean: Steal the Fisherman's Hat as Adult Link
Tip-Top Shape: Find all Heart Pieces