When I was working in "corporate", many years ago, every function we attended was in formal attire. We also wore suit and tie at work. I couldn't wait to get home a change into "comfortable"clothes.
When you talk cruising, I like the two or three formal evenings, the chance to dress up and dine, etc. But, if the cruise lines said - ALL casual, I would be OK with it, but would probably miss a night or two of formal attire.