You get a better room, a couple of snacks in the minibar (replenished whenever you ask) and access to the rooftop pool/restaurant which serves breakfast and lunch with drinks until 8pm

For anyone that is interested, an answer to my own question….they give zero f*cks anywhere about the dress code. Didn’t try Bisou as not my kinda cuisine, but wore shorts every night and didn’t get turned away from anywhere. Granted, wearing trousers doesn’t an outfit make, and I saw some very questionable outfit choices that technically met the dress code but that I’d never be seen dead in….so lesson to be learned is just don’t look like you’ve rolled it off the beach for dinner and you’ll be sorted!