By default, product keywords are sorted by relevancy. By that we mean keywords that are the closest to the Amazon product. Targeting keywords that are the most relevant to your product, help you get maximum traffic. The more relevant your keywords are, the closer you are to your potential customer.
Seasonality often plays a significant role in search volume. By identifying online search trends at the query level you’ll be able to alter the listing content to focus on a specific search query that is trending currently. Also, you increase your chances of finding a larger audience with buying intent for your product.
Amazon provides users the option to complete words based on what most Amazon customers search, what customers have previously bought.
It makes perfect sense to use Amazon auto-suggested keywords in your product listings. If people search for these keywords then there must be people buying the product too.