Flink is too slow for this.

If by features you mean tracking state per user, that stuff can be tracked without Flink insanely fast with Redis as well.

If you re saying they dont have to load data to update the state, I dont see how massive these states are to require inmemory updates, and if so, you could just do inmemory updates without Flink.

Similarly, any consumer will have to deal with batches of users and pipelining.

Flink is just a bottleneck.

If they actually use Flink for this, its not the moat.