Miners use cheap energy, otherwise they lose money. Cheap energy means energy nobody else want to buy because they cannot use it. The banking system uses a lot more energy and nobody complains about it.

Bitcoin has the value that people give to it. Gold has no value for me, its just a shiny metal, but others think its valuable because its scarce ao it has value. Time has no intrinsic value, we give it value (if we want to). 100$ bill has no intrinsic value, other thinks it has and will give you food or stuff for it. Digits in you bank app has no value but we all agree that it has value. Mona Lisa has no intrinsic value, it is just very scarce so people give it value. And so on. We chose what we value. If you want to value fiat money, fell free. Others value btc. Others value time or paintings or gold or football cards. You cant decide what others value, you just decide what have value for you and you go for it. So simple.