Anything's possible... likely? No, it will take you millions of years to find a block on average. As for why they sell them to you, it's because it's easy to sell hardware to people who don't know what it is they're buying if the sales pitch is all bullshit.
I bought on Amazon UK, And sales pitch was that I could earn at least 25 bitcoin per month. If that's really not true I will raise an issue with Amazon
I seriously doubt that, bet that it actually said "
up to 25 bitcoins per month", which is in theory true.