L'homme for me in my current scent collection which is a tab bit limited to some peoples is probably the ultimate day/work scent for a classy environment. I can imagine somebody wearing it with suits in both formal and informal style events.
I'd say it's a bit too classy for 'normal' office wear. I'd rather it be for meeting and greeting banker types to be honest where you're in flashy environments closing deals. That said, my 'ultimate', 'normal' office wear scent from my collection for almost every average level graduate job is Boss Bottled.
La nuit as mentioned is definitely a night time scent at heart. Can be worn during the day, but i think i use specific scents for specific times and situations and as mentioned, La nuit as the name implies itself, thoroughly belongs for evenings. Also not for anything other than very intimate and black tie affairs. Hence, a bit more closed but an amazing scent.
I love them both equally and i'd love to get my hands on the 200ml EDT to go with the 200ml L'homme i picked up on offer a while back. Thinking back, i sometimes think the 200ml wasn't enough at the price it was on offer lol, but then again, even on offer at almost 50% off, it was pricey for a student. Still, 200ml lasts years long with the small amount of time i actually get to wear such scents so it's not a problem lol.
I would reccommend that people try both out as with all scents to see how they would like to live with such scents and in some cases as seen, some just opt for one of them rather than both.