Smog dubs allow every move that's been available since gen 3 (barring illegal combinations) as well as every event/box legendary that's not broken. This includes all the 100x6 pixies, every Deoxys form, Darkrai (Dark Void is banned,) KyuB, Diancie, Skymin, etc.
4v4 and 6v6 doubles are different. Specs Sylveon is an immediate threat to Mega Mence, and it's harder to have a switch-in prepared when half your team is already on the field. This is the same with other ways to handle mega mence like Competitive Icy Wind Milotic or Bisharp; since the Mega Mence user has four pokemon in reserve as opposed to two, handling checks to mega mence is easier (it's unlikely that you can fit in a viable answer to Specs Sylveon and +2 Milotic in two slots while still being able to handle the rest of the meta.)
Follow Me Jirachi is a also huge reason why Mega Mence was banned, the combo of those two was brought up dozens of times in its suspect thread. The two pair together flawlessly, Jirachi's presence means that Ice Beam and Play Rough are simply not reliable answers. You can argue that Amoonguss and Togekiss provide the same support, but they don't; neither are terribly threatening to Sylveon, for one (Jirachi just uses Iron Head,) both are weak to Ice and Rock, neither are as fast as Jirachi, and Rage Powder is negated by Safety Goggles.
Smog dubs also doesn't have item clause. The two metas are simply very different, it's not as dumb as comparing VGC to smog singles but it's still pretty dumb.
>>22660318Because Volcanion and Hoopa can't be obtained through legitimate means. Follow Me Jirachi is something that was officially released, it's something that COULD appear on a cartridge without hacking, as unlikely as it is to run into one that's legitimate.
