Please explain the quality problem a little bit more in detail

I do not think that the issue is focus. The inconsistency with the lights is a problem. However, looking into artefacts, you see clear reasons to refuse this.

The glass is quite blurry as compared to the tortoise 

Poor focus is the main issue.  Except for some turtle parts, nothing's in sharp focus. 

Second issue is light source. The beverage is lit from right side, turtle is lit from the left.  Composites with competing light make no sense visually.  

Amusing concept, though. This could be a clever beverage ad in a magazine or on a billboard. But sharp focus and well-defined edges are essential for successful commercial print results.

Hope that helps.

Is this an AI, a camera photo as posed, or a photocomposite? I'm not sure how to view it, and the glass and the tortoise seem (to my untrained eye) to be lit from different directions. 

Not so much sure if this is really a quality issue as much as two subjects together that don't have a logical reason to be pictured together, thus making it unlikely to have commercial value? Just a guess. Although the glass is a tad out of focus compared to the totoise. Maybe removing the glass and extending the right hand side might help? I can't really imagine an instance where some searches for "a tortoise on a table sitting next to a cocktail."