Same here. Threema sounds best on paper. I'm definitely going to try to use atleast within my family. But, I don't hope to have a thriving network around it any time soon.
Too bad the masses don't get the privacy angle in free products. I feel like FB<->WhatsApp is counting on just that by using a unintuitive "opt-out" policy. The moms,dads, and not so tech aware citizens won't even know what goes on underneath. They would be feeling falsely proud to use a 'secure','E-E encrypted' service not knowing 'privacy' is different from them.