WEBNOVEL_OFFICIAL
Honestly, being able to read for free for a day is okay, but if you can't read all 300+ chapters in one day then it is better to have a discounted chapters and buy all the chapters to read them later. Or reread the story.
Also, if there is no notice of what stories are free on which day, then if someone buys several chapters only to find out that it is free the next day, it will cause a heartache.