Yeah. Seems a bit hardcore at face value but I guess it’s more about preventing the pizza and KFC parties, and making enforcement easier. Also allows diversion of resources to daytime enforcement/monitoring - PSOs usually on trains etc can be redeployed to daytime community beats etc.
And if you look at the curfew rules, apart from exercise, you are allowed to move for work, chemist etc.. Depends on what work is left mind you..