This is very good advice. For many people it is useful to think training week as an individual thing, and not force it to 7 days.
I like training like this, it gives options to train 2-4 times/week by how you have time/can recover. It would feel quite dull to go to the gym just to hit assistance. I don't say it is useless, but I would prefer do something more focused when I get the possibility to train.
I have had success when using either Squat, DL - Bench, Press OR Squat, Bench - DL, Press split, but anything works.