Games are not produced in a void. In most cases they emerge from a process of iteration, with existing games used for inspiration. Similarities to these games are apparent in a variety of aspects, the most important of which is arguably mechanics. In these cases it is a wise idea to make the control scheme for these mechanics similar to those games that already exist.
Similar control schemes make the game easier to pick up for new players, if they have played games in the genre before. They know generally what to do and have already spent hours using systems that are already familiar to them. Keeping the same general control scheme helps to avoid frustration, both when playing the game for the first time and when switching over from playing another game.
Rayman: Origins is an example of a game that keeps its control scheme similar to others in its platforming genre. On Xbox, A is used to jump to other platforms, X for attacking, and the joystick for intuitive movement. This makes learning the game easier for newcomers and is automatic for those who have played platformers before.