It's in the Legend rank duels. Keith players use the Thunder Dragon deck to put the dragons in place for his baggy sleeves skill. And since players can use the skill on their next turn their opponents are already at a disadvantage
Neos Fusion doesn't properly Summon the monster, so a monster Summoned by Neos Fusion can't be revived with Double Hero Attack. And if you're just trying to revive one that WAS properly Summoned, Neos Fusion prevents you from Special Summoning for the rest of the turn after it resolves.
I use it in a psychic deck, it's a good trump card option for a duel that drags on. if I draw early I normally bait the opponent to destroy/banish it. Only gotten to legend rank so far though on this deck so make of that what you will.