In the world of digital coins, so bright, where every trade can change your night, a riddle lies, a mystery deep, in blockchain's code, our secrets keep. What is it that starts with a "B," and holds the key to all we see, yet isn't gold, nor silver gleam, but makes our wallets grow, it seems?

Cryptocurrency! The riddle beautifully captures the essence of digital coins and blockchain technology. It highlights how cryptocurrencies, starting with a "B," hold the key to financial growth and security in the digital age.