So you were born (or at least live) in a country that has a stable currency which is accepted almost everywhere, and you can trust your politicians to not undermine this currency by bad economic policies and/or creating very high inflation. Congratulations! However, a large part of earth's population do not enjoy this stability. For them crypto offers a way to store wealth that cannot be debased nor easily seized by authorities in bad faith.
Some estimates are that 2 billion adults do not even have banking.
You say your currency does not waste tons of energy. How much energy would you say the financial system in your country use in order to keep a sound ledger and enforce the monetary rules & policies?
Bitcoin uses less energy than the gold industry. And gold mines wreck the environment (https://earthworks.org/campaigns/no-dirty-gold/impacts/). But you don't hear much about that even though most gold is used as a store of wealth, much like Bitcoin is.
Energy usage should also not be equated to bad energy production, though of course miners can use bad energy source instead of sustainable energy.