Ignis appreciates the discretion. He doesn't want to take up more of Rhok's time than necessary. Although Rhok would have enjoyed it.

"I'd rather arrive refreshed," Ignis replies after a moment of thought. "It wouldn't do if I made everyone's first impression tired and dirty from the road."

Practical, but Ignis isn't against staying in tents. He just wants to look like a man of refinement. Being a part of a royal court means proper hygiene.