Short-term goals are important in life and in games. In my experience, people are extraordinarily bad at long term planning and “seeing the big picture”. Perhaps it’s an evolutionary hold over from the immediate need for survival. For whatever reason people can get lost if the goal is too far away or too immense to fathom. In games this can lead players to become disengaged, take excessively long turns, or just be confused.
If your game is short, then winning can be the short-term goal. But if your game goes on for more than 30 minutes, I think you would do well to have some intermediate goals for your players. These give them something to work towards without overtaxing their ability to plan.
Short-term goals offer a few benefits in your game. They can allow a player to build their strategy over time. If players need to think over their entire game plan at the start they will need to take some time to do that. However if they only need to plan to their first short-term goal it is much more approachable.
They allow new players to get into the game more easily. Especially if the initial goals are straight forward. They don’t need to understand every rule yet, just the few rules that let them get to their first goal. Then they can learn more to get to their second goal.
They allow players to roughly gauge how much progress they are making in the game. While a lot of games keep who is winning intentionally nebulous, knowing how many goals you’ve completed compared to your opponents can give you a rough idea of how you are doing in the game. Though goals do not have to be equal, 3 goals for one player may be more than 5 goals to another.
A variety of short-term goals can allow a player to map out their strategy. This is how many tech trees work in games. If I want to be able to use lasers, I have to first learn optics and electricity, but I can ignore cooking and gambling. Again, this can simplify an otherwise overwhelming game by allowing players to ignore sections of the game and focus on their strategy.
Having multiple paths of short-term goals to win a game helps the game to be more replayable. After wining one way players can try and win in a variety of other ways.
Give your players many things they can work towards and achieve in a game. Even if they don’t win, they will have a sense of accomplishment from completing short term goals.