Why would someone lower their deadlift sets instead of treating it like another exercise?

I was reading the incorporating deadlifts section and it recommended to use one of the three options since I assume deadlifts is taxing. I’ve been used to deadlifting 3 work sets in session B of Zulu block, not noticing something wrong after. Is it personal preference thing where it’s just based on how people feel and I should just continue what I’m doing, or should I lower it to 1 set per session B? I would also like to understand why would someone not treat it as another exercise and what makes it different.