Submitting an extended list of keywords may be not be useful. In fact, you won’t get as many potential customers to your website with an extended list of keywords as you would with focused and targeted keywords. Besides, you would also end up paying more without any benefits.
Targeted keywords would ensure that only those visitors who are actually interested in your product or service click on the search listing and visit your website. Thus, there are more chances of a visitor becoming a loyal customer.