It’s the same thing as far as I know. And the concerns I mentioned apply if you buy the whole root, not the root processed into flour (it’s already been processed).
Ethnic stores are a godsend btw. You can get stuff that would normally be labelled as “gourmet” in a regular grocery for dirt cheap.
Yes, there's one very near us. The regular groceries are starting to get some things because of the population here, but there are still things that I like but can't find outside of the ethnic stores.
One of my favorite things is this ginger candy in the blue checked wrappers that a Korean friend first gave me (it's very strong, though, and might be an 'acquired taste':
