99.9% of the time, paying with bitcoin goes through a payment processor such as bitpay, bitpay instantly sells your bitcoins for FIAT hence putting sell pressure on the market. So basically if people take your advice right now and start buying products with bitcoins, the price will fall.
No that is a myth.
The reason the BTC price is falling is that miners are selling immediately, and not hoarding.
I never claimed it was the primary reason for the falling price.