Depends on your goal. If you really just want a blinking thing, maybe buying a ready-made one is better, or alternatively building the one you find easiest. If

Depends on your goal. If you really just want a blinking thing, maybe buying a ready-made one is better, or alternatively building the one you find easiest. If you want to make a product, whatever maximizes profit is better. If you want to learn about microcontrollers, build it with microcontrollers. If you want to understand how 555s and RC charge/discharge curves work, build it with a 555.