In the end, it is your customer who will define the value of your product. Those marketing and PR can get your sales, licensing done only for a limited period.
As a founder, you must be having a great vision, roadmap, and expectation. But if a customer fails to get those rewards from it, their perception will go dud.
All your design, market research, UX, and product development will go to waste. Instead of building perception about your product via social media marketing, PR focus on customer’s pain and works towards giving them a painkiller.