If you are paying money to Google, Facebook, etc. to drive traffic to your website, you need to eliminate ALL guesswork for the visitor. Below is an example of a potential customer getting lost from point A (the ad) to point B (the sale).
You need a landing page with ONE clear action. In most cases, your home page is not a landing page, because a typical home page is going to have a number of different possible actions for a visitor to take. This is where you can lose them (and money) in the process.
Create a landing page with one action. Don’t create confusion or decision fatigue for your potential customers or clients.
(This really applies to all traffic, not just paid traffic, but I focus on paid traffic because you could potentially waste your ad money if you do this.)