Pretty much. Since most priority users can't switch safely into a Terrakion, you may be able to grab both a Substitute and a Swords Dance boost depending on what Terrakion checks the opponent is using.
The other main candidate for setup is Pokemon such as Scarf Landorus/Infernape locked into Hidden Power Ice. Particularly in Sandstorm, they may not be able to break the Sub even if they stay in, and since they can both serve as Terrakion checks themselves, you can potentially force them to give you minimum 2 free turns before they can get back in.
If sand is up, +0 Genesect locked into a neutral move isn't TOO bad, although it's more of a clutch thing since you'll still take a chunk. Best if Genesect is important to check something else you have so the opponent cannot really afford to risk it.
The other main candidate for setup is Pokemon such as Scarf Landorus/Infernape locked into Hidden Power Ice. Particularly in Sandstorm, they may not be able to break the Sub even if they stay in, and since they can both serve as Terrakion checks themselves, you can potentially force them to give you minimum 2 free turns before they can get back in.
If sand is up, +0 Genesect locked into a neutral move isn't TOO bad, although it's more of a clutch thing since you'll still take a chunk. Best if Genesect is important to check something else you have so the opponent cannot really afford to risk it.