With a business card one doesn't need to talk too much. The information in the business card will provide the basic information about you and the type of business you do. I'd say it is still very much advisable to have them.In the digital age, a lot of people believe that business cards are no longer useful but I still believe that business cards can still be a useful way to market your product or business. It helps even when you have an online business. Business cards are an easy way to introduce and inform about your business.
Yes, it is an excellent cover letter, you do not need to be giving many explanations about what you do, the card will say most of the necessary information.With a business card one doesn't need to talk too much. The information in the business card will provide the basic information about you and the type of business you do. I'd say it is still very much advisable to have them.