It is intentional. The idea is to force drivers to reduce speed, and the mechanism is because it isn't familiar to the drivers. The claim is it forces them to be thoughtful.
Whether or not it works or is a good idea is not something on which I'm opining.
It's basically always safer to make a higher speed driver uncomfortable continuing at high speed. Reducing high speed through driver discomfort is 99% of what saves lives in road design.
Whether or not it works or is a good idea is not something on which I'm opining.