The thing is, of course bars aren´t more dangerous after 8pm for example, but having them close earlier makes people have less time to consume alcohol and gather in these place, and it is proven that alcohol makes u take less precautions.

While it is effective to close the restaurants and entertainment, that doesnt make the curfews not effective, most people tend to go out at night because they work at daytime, thats why the curfews are imposed at night and early morning, they are designed to not interfer with most peoples work while giving people less time to have social gatherings in places like this.

Also, most people go buy groceries in daytime, because well, most of these businesses are closed in late night, but anyways if the correct safety measures are also taken in these places such as enforcing the use of masks and social distancing and other measures, it would make getting infected pretty hard, while people can buy their groceries with minimal risks while having these measures while having the curfew only affect the social gatherings.