Many thoughts but the predominant one is WHO CARES. I hate questions like that. 1 true working set is enough to stimulate growth but you are not going to walk in the gym do a few warm up sets and do one working set and go home. Just do what you want to do. If you want to do low volume do it because it will work as long as you go to failure and you can still fit in many sets and various exercises in a 30 min session for example. If you are late to the gym the gym before work due to traffic and you only have 20 mins to train then go all out for 20 mins but under any other circumstances why would anyone want to do the bare minimum everyday in the gym.
If you don't have much time because you work loads then sure fast workouts and hit it hard and be out in 30 mins. Although if you are like most other people and enjoy the gym just do what you want to do and what makes you happy. As long as you are not doing failure set after failure set after failure set and spending hours in the gym destroying your body you are going to be just fine. Just adding the other day I was late for the gym and it was closing and I had 40 mins to train and I went crazy pushing it and barely resting between sets and the sweat was pouring off me and I was pretty much done in just over 30 mins and this was far from a low volume workout so you can fit in a lot in a short period but me personally I would rather allocate sufficient time for me to warm up, perform every exercise I want to do with rushing through them and then having time to stretch and go in the sauna and shower.
So whilst some may want to not waste time in the gym who really wants to do the bare minimum because you could stimulate growth effectively in 10-15 mins in the gym (4 warm up sets and 2 working sets for squats for example) but for optimal results doing a bit more and hitting each muscle using different movement patterns (exercises) is always going to better.
I wasn't advocating for doing the minimum, rather the oppsoite
Say I have weak triceps. I will have my regular tricep day, I can't do it like you and train instinticve or limit my time, I go at a certain time and have a planned routine and make sure I have time to complete all my sets, I just like to log things very careful and ensure im doing the same week to week so I can ensure progress (like DC training). Just how im wired I guess lol.
But anyway, say triceps are weak. So I have a bro-split, with an arm day. But they are weak so I want to hit them more often, but I only have so much time in the week to train. So I throw in a single set, or two sets, of triceps on back day, chest day, and delts day. At the end. Rather than change my routine that I like to now hit them twice, just throw in an extra set each day.
But ive heard some speculate you need at least 4 hard sets for it to even be worth while. But this particular study shows thats not the case.
So a possible way to bring up say,,,triceps, would be to have your arm day in a 5 day split. Then on those other 4 days, bang out 2 high rep sets of triceps after. I think this could be useful for people who like to do a bro split (chest, back,legs, off, arms, delts, off)