Your second flight is not necessarily 90 mins. Lounges are also great when you are departing a country , especially if you arrive early for your flight. Emirates has many desks open long before in most country’s . Just travelled With Swiss Air business Bangkok to Nice via Zurich. The layover was 3 hrs, so I got a nice meal and drinks. When an airline offers you an upgrade, the price depends of how close your flight date is, or vice versa. Also I like the free pick up to your home in a nice car, ( depending on distance , less hassle. Then also, you get better food and drinks with business, Altho I must say Emirates is not as good as it was. Hence my flight with Swiss Air.