scams most likely but I mean honestly if you want to be safe just don't buy from anyone with a brand new account or like 1 rating (whether we're talking Ebay or Amazon).
What's interesting is that pretty much universally if someone is faking selling 10 Switch's cheap on Amazon and never sends them out.... everyone is going to get refunded by Amazon (who has reach to the payment) pretty quickly.
I've heard before that these 'scams' are often not to get the money directly, because thats near impossible (the payment will probably be held if its a new seller), but more to possibly gain the personal information of people (addresses / phone numbers / etc.) and that that data can be sold or something like that.