Well, considering that many marketing methods are cheap or free, it seems foolish not to take the opportunity to get your name out there and to let people know what services and goods you provide. For instance, a small business owner could print some fliers and post them on bulletin boards around town, can create a Facebook account for the business and share specials and other tidbits to gain interest, and can list the business on Nextdoor if the community has an active page. Word of mouth recommendations are great, but why not take those other opportunities too?
I get a lot of business from customer recommendations which I truly appreciate, but marketing is an essential part of my business too. I don't think many people are going to convey your hours, phone number, email address, a list of what you offer, and whether you make local deliveries. Word of mouth advertising might look like,"Hey, I bought the most amazing apple pie from OhSusanna's Market Store, you should check it out." But that potential customer might not like apple pie or they might need something entirely different down the road and they won't know that you also make custom furniture, full suppers, and artwork. Marketing is an important step that's best not forgotten.