Yes, Che Guevara was communist, but Fidel Castro was opposed to it until the US branded him as one. At that point he had no choice but to embrace the Soviets. That said, we've never seen real communism on a national scale. We've seen autocracies hiding behind a communist banner. The central tenant of communism is worker owned businesses, not state run economies.
All states lie on the autocratic-didactic scale somewhere, and the only way to make that happen is having a violent enforcement class. You just can't get away from it, and suggesting that a system like this can be instituted without defiling the natural rights of whatever amount of people disagree, minority or majority, is wrong, and you are morally unsound to even suggest it.
Property is not theft, top-down state communism is theft. Steal from me, and I will defend my property, you risk the consequences of my defence against you aggressing against me. I don't know why you are suggesting such illiberal and immoral nonsense in a Bitcoin forum, Bitcoin is the one technology of the age that thoroughly defies state power of all stripes.
Certainly not an entire nation-state. Communism is alive and well on a small scale embedded in every nation. Even in the uber-capitalist US, there are companies who are nearly entirely employee owned. There are many advantages of such a structure, starting with the ability to look more at the long term consequences of decisions rather than focusing on the next quarter's earnings.
Here, we agree.
Employee owned co-operative enterprise, which is simply communism or socialism applied in a different context, and called by a different name, has very clear advantages over top-down corporate ownership model, especially for mature markets. But it must be voluntary, not mandated by official violence as you did when you endorsed state communism. And these enterprises must be careful to make sure competitors do not infiltrate their workforce to abuse employee rights against the overall interests of the overall goal of said enterprises.
And remember too that there is an obverse to the advantages of cooperatively owned enterprises; as a structure, it can cause serious problems for enterprises that need alot of innovation to achieve their aims. If the employees cannot grasp the apparently eccentric vision of one individual, then the freedom to experiment and innovate can be stifled or even destroyed. Allowing company leadership to choose their ownership and decision making model is, therefore, of paramount importance. One size does not fit all.