Search engines (such as Google) use the topmost text on the page to display snippets (quotes from the page) in their search results.
Because the banner is text, and it's on top of the page HTML, it results in the following view:
There is approximately 0% chance that anyone would click on a search result like that. It looks too non-relevant to what the user is searching.
Proposed solution: make this banner into an image, so that Google can't use the text from it in snippets.