Being able to score from a post-up position is a useful skill for players of all sizes and positions. In the post you are starting your attack from a much closer position to the basket than when you are on the perimeter, which, practically speaking, makes your chances of scoring greater (see the shooting percentage leaders in the NBA -- always post players filling the top spots).
Many times, a player who is taller than their teammates get placed in the post because they are the biggest player. This is not a negative situation to be in -- a good player is a good player at any position. Kobe Bryant and LeBron James both played center defensively for their high school teams. When LeBron’s high school team ran a set offense, LeBron was on the low block. Kobe was the tallest player on his HS team, and led them in blocked shots and rebounds. Did they complain? Kobe knew he was good; all he needed was to be in the game, period. This is the mindset of any good player.
And, even when you are playing the position you wish to play, having the ability to score posting up will make you a valuable asset.
The most important aspect of post scoring is footwork. Your footwork is the difference between an easy, make-able shot and a tough, well-defended, blocked or missed shot.
Lastly, understand that there is not a set move or set of moves that will always work as you move up in the game. Opponents adjust and have different capabilities and experiences as you move from game to game. Never assume that what worked yesterday will work today. Have enough in your arsenal to take advantage of whatever the defense gives you. This is where your attack originates.