If it uses Bluetooth you're theoretically on the hook for thousands of dollars if you want to sell your ESP32 project as a product. (IANAL; it may take a lawyer to truly understand if you have to pay or not.)
ESP32 modules (read: not just the packaged ICs) are pre-certified in most markets. This is the main advantage of shelling out for these more expensive modules instead of just integrating it all yourself. It's also why many of the IOT products which use ESP32s use modules and waste a lot of area rather than the much smaller ICs: certification is a nightmare for small scale products!
