I'm looking for a word or phrase that expresses the idea that something can be done well at the beginner-level, but can also be extremely rewarding when someone reaches an expert level.
The concept being that someone's efforts can be rewarding and fruitful even if they have just begun to learn this task, but also has a great deal of expertise that experts can appreciate.
Two examples that I have are rather specific, but I'll include them to try to help establish context:
In the video game Team Fortress 2, the Soldier class is very easy to use as a beginner, because explosive splash damage and spam are easy to use without much skill. But a more experienced player can use the Soldier's ability to rocket-jump to excel beyond almost any other class in the game, with incredibly high mobility and damage output compared to any other class. A beginner can contribute, but an expert can become extremely powerful.
Likewise, the Cleric class in DnD 3.5 has the incredibly useful party ability to heal other players, making them invaluable even for very new players. But they also have the ability to become one of the singluar most powerful classes in the game in the hands of an expert.
That is the type of quality I'm trying to find a word or phrase for - something that is easy to learn, but rewarding to master.