I'm not against virtual currency or whatever and I'm not endulging myself into conspiracy theories either. My beef is that we really don't need something new in this world
Pardon? In the field of currency & banking we most certainly DO need something new. To say we don't merely demonstrates that you somehow haven't noticed the serious structural/political flaws in the current global financial system, which everyone who pays attention is well aware of. Search terms: fiat currency, fractional reserve banking, private banking cartels, currency creation via loans, rigged gold & silver markets, US Federal Reserve is a privately owned corporation, Creature from Jekyl Island... just for starters.
which wastes a lot of energy while everybody is (forced to) conserving energy.
You absolutely haven't demonstrated that the total energy used for bitcoin mining is significant in any way. Especially relative to other large scale computing systems such as google searching, cloud computing, HF trading, and even the poor design of standard html/CSS/script which places much of the web page display calculation burden on Clients (every time), rather than the Servers (once.)
You can't argue against that or claim its insignificant.
Yes we can.
The people behind bitcoin could have developed different methods for a gradual release of bitcoins.
You need to propose at least one viable alternative before you can claim that. I bet you can't.
Btw, the only 'indulgence' related to conspiracy theories, is to pretend that the world is run on an 'open' model, and that the wealthy and powerful never do things in secret among themselves that you wouldn't like if you knew about it.
This is an extremely naive, even stupid assumption. Edward Snowden would sneer at you, and so would Michael Hastings - if he were still alive.