From Zenva Academy: "Some games have a fixed number of levels created by a level designer. This way, the designer can create the levels so as to provide the desired gameplay experience to the player. However, it reduces the replay value of the game, since the levels will always be the same every time they are played.
Another alternative is to procedurally generate levels using an algorithm instead of a level designer. This results in a virtually infinite number of levels, and the player will never play the same level twice. However, since the game designers have no full control on the levels, they probably won’t be so good as if they were generated by a experienced level designer.
Each kind of game level (manual or procedural) has advantages and disadvantages, and can be applied in different kinds of games (both strategies could even be used in the same game). In this tutorial, we will procedurally create a dungeon with multiple rooms, using a simple algorithm. Notice that there are several ways of doing so (as you can check here), and each one can be recommended for a specific kind of game. So, if you’re building a game and need procedurally generated content (not just levels), take a look in different approaches to see which one better fits your game."