My worry is that we will continue to see the pace of international money transfers increase as competition, trust and infrastructure improves. Bitcoin, on the other hand, is limited structurally by the very mechanism that guarantees its accuracy. Today miners burn 77Kwh of energy to mine the block that records your transaction[1]. Sure hashing tech might get more efficient, but the block mining complexity increases to keep their discovery rate constant at one every 10 minutes[2]. This does not set a cap on the energy usage of mining for the network.

1. https://www.vice.com/en/article/ywbbpm/bitcoin-mining-electr...

2. https://digiconomist.net/bitcoin-energy-consumption/