I actually don't mind the day-of-interviews thing because I find it fair and encourages hiring efficiency. For example, if I lose a day to do 6 interviews then the company loses 6 engineer-hours (+ time to write and assess feedback). That will discourage doing a large number of interviews with a low hire rate.

OTOH, I hate having interview "homework" because they take a lot of my time but cost the company almost nothing - they can easily have a hundred people doing the homework, get one engineer to spend a day evaluating them, and then only hire one person.