Just to add a bit of context and describe a subject where such generator can be useful.
Let's say we are building a turn by turn game in JavaScript or TypeScript (2048 for instance). Each time the player plays a round the IA uses an internal random generator to guess its next move (adding a 2 or 4 in the grid). If we want to add some kind of cancel operation, then replaying the user input might lead to a completely different situation given we use unpure random generator. Using a pure one we just have to ask the generator again for its value.
Such problem can easily be encountered in implementations of 2048 allowing the back operation.
Let's say we are building a turn by turn game in JavaScript or TypeScript (2048 for instance). Each time the player plays a round the IA uses an internal random generator to guess its next move (adding a 2 or 4 in the grid). If we want to add some kind of cancel operation, then replaying the user input might lead to a completely different situation given we use unpure random generator. Using a pure one we just have to ask the generator again for its value.
Such problem can easily be encountered in implementations of 2048 allowing the back operation.