It's easier to build something for your target audience if you're in it.
The idea here is simple. Scratch your own itch. Building something you want to use yourself is easier than building something you can’t relate to. If you have a personal interest in the result, if you plan to be the biggest fan of what you're creating, that investment will inform a product you couldn't build otherwise.
You don’t need research to know where the hole in the market is, what the challenge is or what the audience wants. You don't have to find the market. You create it.
Research is still helpful to reveal blind spots and biases, but that’s beside the point. No matter how much research you do, the product you build for someone else will not be the same as the one you build for yourself.
Everyone has an idea for an app these days. Everyone fancies themselves an undiscovered genius. Building a great product requires more than the idea – it requires strategy, luck, timing, talent, connections, money.
But if you want to create something that solves your own problem, something you plan to love and use yourself, you already have a head start.