Can the design of a website affect it's SEO and usage
So many times I've ran into people who have just god awful websites and I wonder how they get so many sales each day. The only idea I could come up with is that they get the "Buy Now" button right in front of the person as they get to the website and jam it down their throat pretty much lol.
You can do all of that and have a well designed website that functions perfectly for the search engines as well. You just need to know a little bit about marketing and optimization
First off you'll want to make sure your code is mobile friendly, or responsive, just so that if someone comes to your website via a mobile device like a cell phone or tablet that they are having a good experience. If your pages are not responsive, the user will have to do what I like to call "Pinch and Pull" where they basically have to pinch their screen and expand their fingers to zoom in to see what your website has on it. People actually hate this now that everyone is getting use to mobile friendly websites, so just get responsive already lol.
The overall layout shouldn't affect your optimization too much if you do proper on page optimization. Your pages could look like they were made in 1997 but if they are optimized up to Googles standards as of today then you're fine. I've actually had clients hire me to make their pages responsive but they wanted to keep the same feel and look because they didn't want their dedicated members to think they moved or sold out lol. We did it with as little tweaks as possible and the design looked pretty much the same, but now people on their phones could read everything well I didn't like it, but the client did
Using a website that isn't designed well can be frustrating or feel like it's lacking. You could have your links and menus all over the place which make it annoying, and people wouldn't stay. Or you could have it designed very basic, like my client I talked about, and people would feel like the website doesn't have much on it.
With all of my designs I like to have that wow factor when a person gets to my homepage for the first time. Whether it be a nice slider or a random feature in the FAQ that has drop downs for each question, the littlest tweaks to your code could change a lurker to a monthly commission
So get out there and make some money from you awesome website