Well, first it seems to me that it is another fiat currency with the significant difference that its validity comes from its crypto status instead of because it's issued by a nation-state.  This puts it on the level with other alternative currencies, which are often created to (1) protest the stranglehold that the financial empire has on much of the world, (2) create an insular local economy not as prone to price fluctuations (when it's robust enough) and market manipulation, (3) to allow like-minded individuals to use a different way of exchanging goods and services that is, at least in theory, less visible to the government, and/or other reasons.

You can argue that it has value because WikiLeaks can profit off ownership of BTC, which is great, but BTC is also used by other "ventures" that are definitely criminal and/or evil in nature, thus it's a balance (in theory, if not reality) and we cannot look at the limited rationale of supporting WikiLeaks (no matter how noble their efforts are) when speaking of something that is far-reaching and equally available to "good" and "bad" groups and individuals.  Money is money, and it has no inherent moral value.

I'm not an expert on this topic, but it boils down to the fact that BTC has value because people choose to accept that it has value and are willing to speculate on its future for the above reasons (and more).