Aesthetics aside, building within the game does force me to plan better. When I start a new seed I take days just to find a site and then collect materials since I tend to build raised terrain citadels with moats, etc. This along with teleport restrictions and "the grind" can really stretch out a game for those of us who are overly cautious (day 700 before I even entered the Infested Citadel) but I'm sympathetic to some form of creative mode where we could at least try blueprints and perhaps gauge the area and material costs of some of these structures we see in videos and screenshots.