Question

Why is it important to be aware of marketing tricks?

Answer 1

Because people in the market can use it against you / scam you.
If you know someone doesn't have any prior knowledge of what you're selling you can easily say," this helped my grandma cure her cancer" etc. You could easily be used if you're not aware.

Answer 2

So that no one can take advantage of you. There are also companies who will sell a cheap product for an expensive price.