If an easy tick is provided, then users will turn on an autoupdate by cron, which is something that the developers don’t encourage. A user is free to write their own cron if they choose, or use
pihole -up from the terminal, but the developers aren’t going to add a feature that does something they recommend against doing.
Users should not be auto-updating the software, they should take a look at the release notes and decide ahead of time if they want to update to the latest version. Think, then act. Not, act then regret.