Really? Only one application of computers --- Bitcoin --- wastes countries' energy usage and yet it doesn't make sense to optimize software for ecologic reasons?

No, but there are plenty much higher targets before going after computers, especially compared to the insane value they produce. Like, is that single server running all the logistics of a country’s train network “inefficiently” really significant compared to.. the inefficiency of even a single train?

What about those billions of devices running software in gadgets, phones, TVs, routers, dishwashers, etc ?

Crypto uses vast energy as a feature, a side effect of maintaining a competitive environment as part of proof of work (other staking mechanisms are different). You could not optimize this to use less energy.