Please separate workdays from weekends when asking for availability times. People that have a job can only play in the evening during the week but all day on the weekend. Why not separate this?
It seems they are mostly asking for a “general” time. So if you are available 9pm-4am on 5 out of 7 days of the week, you should click it because you are “generally” available during that time.
I doubt they are using your availability times to decide wether or not you’re allowed to play and test the game, rather it’s for figuring out what time/days they should start and end Flight tests/betas.
So in that sense, it makes a lot more sense for them to put more basic selection options rather than custom ones. They just need a quick pie chart to look at so they can make a choice when needed.