I use this site for my website and I will steal the code from anyone whose site looks good.
Yar matey!
The problem with these website builders though in my experience is they can create bloated websites which are uploading too much unoptimized code to the visitor. That to me is a big problem.
Personally I'm more focused on
optimization and speed rather than flashy design, because to me a website that loads instantly on any device, anywhere in the world, is a lot more impressive than some nice design. Google also feels the same way, your rank will be majorly influenced by how fast it loads, and other optimizations, which these builders simply can't prioritize.
For example I found a website made with systeme.io
Code:
https://www.annacomerford.com/
And here's the page scores from Google:
Code:
https://pagespeed.web.dev/analysis/https-www-annacomerford-com/ibrerk2nzb?form_factor=mobile
The scores are pretty terrible for both mobile and desktop (pictured below). This is going to hurt any attempts they have in ranking, no matter how much is invested in off-site SEO - the property all that energy is going towards is hurting it's own potential.
That example site, on a fresh visit, takes about 3 seconds to load which is not bad. But if I had complete control over the website and could tinker with everything, I could get it down to 0.5 seconds. Loaded before you can blink.
Personally I'd suggest that once you use these builders to make a layout and content that you are happy with, have some professional developer convert it into a much faster website and let them know that's your top priority. It shouldn't be an expensive job since you've already done all the heavy lifting, they just need to tweak certain things and do some tests.