¿Que puede ocurrir si no hace esto correctamente?

You won't get high search engine rankings if you submit your website before optimizing your pages. Submitting your website to search engines is pointless if your web pages are not search engine ready.
 
If you don't use your own domain name or if your website is hosted by an unreliable web host then it is likely that your website will not be listed on search engines. If the submitted website URL is only a redirection or a welcome page than it's also likely that search engines won't index your website.