It's been something to "worry about" on PC Engine CD for years also.
I'm pretty sure my copy of Snatcher is legit; even came with an old receipt from its purchase in Florida back in the '90s, stuck against the back of the box - in front of the promotional spiel, but behind the plastic; wasn't TOO hard to remove it. (He paid a fourth what I did. ._.)
Its probably nothing widespread, and I know about the Sapphire repros... Even more reason to try to go complete when you can I guess.
That being said, i'm late to the party on realizing just how Asura's Wrath is just a HD Sega CD FMV game
The guys in the video are being pretty harsh. Yeah, straight up bootlegs are shitty especially (or exclusively) when sold as real versions, which the thing they are talking about can and will lead to, but repo stuff isn't bad. They seem to really hate any kind of repo stuff.
Yeah I dunno why someone would have a problem with repros in general. Translated games or hacks being played on actual hardware, in a cool looking cartridge? Yes please. Now bootlegging stuff thats available in your region and in your language? Now thats a no go.
I suppose its not really a problem if you're buying online anyway. Just check it like people do with MVS carts, and then get a refund if fake.