I had all-day interviews for my job too, including lunch. For me, they were already pretty sure I was the right person to hire, so it was only the one round of interviews. I was even a few minutes late due to my employer having several buildings and the one the interviews started in was unmarked. I showed up early to the wrong location.

That being said, while a single round of all-day interviews isn’t bad, it would really suck if you had to do that multiple times, and would likely be a waste of time for everyone involved