Don't know in detail, but Guildwars 2's code is built in a way they have legit semi-pvp-but-actually-minigames, such as mario-kart style races, or dashing to collect coins like Sonic, or even things like platform/jumping/launching based dodgeball. It's not amazing, but it's at the very least interesting and something to do outside of the main game.
In addition, the jumping puzzles are just generally fun to do and feel more akin to playing a 3D mario game than an MMO.
FFXIV's biggest problem is they tacked on a jump system late into the game, so when you jump you have no control over movement while in the air. Rather than actually jumping, the player is more "teleporting" to their landing site. This means we can't have things like "jump over the laser beam", and can't really have fine control in a jumping puzzle environment. Moreover, the game has wonky hit boxes that make no sense.
Try the Kugane clock tower to see what I mean; what is an exercise in cheesing the system involves standing/landing on invisible platforms for hours of frustration on your first try would be like.. 10 min in guild wars 2.
More of a personal thing, but as a player who is (probably overly) confident in their jumping-game skills, FFXIV is incredibly frustrating. And this is coming from someone who has 100% the siteseeing log.
Anyway, long story short, better physics is just fun. It's just genuinely fun to blaze across the map on my roller beetle and rocket off walls or up ramps (it's like a sonic the hedgehog motorcycle?).