Good graphic design will attract a larger audience. It instills confidence and speaks to the quality of services you offer.This in turn will increase the over all effectiveness of your marketing campaigns and will be a positive enhancement to your customer's experience. Don't sleep on the impact and importance of good graphic design.
Food for thought:
"In terms of visual content marketing, 32% of digital marketers claim visual images are the most important type of content. Blogging comes second at 27%, followed by videos (24%), live video (9%), and podcasting (1%)." ~ Social Media Examiner, 2019