BIP 300, referenced in BIP-300, sets the stage for drivechains: specialized sidechains that Bitcoin miners also secure using the same proof-of-work. Bitcoin is ‘driven’ into these sidechains and can come back, ideally without reliance on trusted third parties.

Supporters believe drivechains could experiment with different features—like privacy enhancements or alternate scripting—without affecting mainnet consensus. Critics worry about miner centralization risks and the complexity of policing sidechain withdrawals. Either way, BIP 300 is a significant proposal for expanding Bitcoin’s ecosystem while keeping BTC itself the universal token.