To be honest, it probably isn't looks. If you are a high-level competitive player, looks are the least of your worries. There is probably a very small percentage of people like that though. Now that that is out of the way, we can move on. One major reason I can think of why V-Create is rarely used is because of the current state of the Meta. Introductions of Rayquaza, Primals, And Zacian have made the Meta extremely Offensively based. This being said, moved that lower your stats often force switching and can lead to substantial consequences especially if you are forced to switch against one of those Major Threats. With V-Create reducing your Speed, you can only stay in 1 or 2 turns before you have to switch out. Also, even though Primal Kyogre is less common now, it is still common enough to make users wary of using V-Create on a set. This one is a possibility. Now, On many Smogon Sets, V-Create is also exchangeable with Earthquake. Earthquake provides the same coverage as V-Create minus Grass, Bug, and Flying, but also has the Additional coverage of Rock, Poison, And Electric. However, the Bug and Grass are covered by Dragon Ascent. While you lose coverage against things like Ferrothorn, you gain advantages against things like Primal Groudon and Zekrom. Also, usually Dragon/Swords Dance are run on most sets that run Life Orb. These reasons are some I believe why V-Create isn't as oftenly used On M-Rayquaza.
Hope this helps!