The verdict
For a small team that needs a working website or a simple shop live quickly, pick Wix. You can build the site, connect payments and publish from one login. You can keep editing it yourself afterwards.
For a single page to test an offer or collect sign-ups, pick Carrd. It is lighter and quicker, and there is little to learn.
I'd not choose either for a design-led marketing site that will be tested and tuned constantly. For that, look at Webflow or Framer.
Both have one thing in common that is worth planning for: leaving later means rebuilding. With Carrd that is cheap because the site is one page. With Wix it is a bigger job, so treat the choice as a long-term one and keep your copy and images in a form you can reuse.