Yes, once you cancel the old hosting, you'll just connect your domain to Webflow and publish the site from there. No need to keep paying the old host after that.
Mark I.You must point the DNS to Webflow for your custom domain (like yourdomain.com) to show the new Webflow site. Publishing the site in Webflow only makes it live on the .webflow.io domain unless you connect your custom domain and update DNS records.