I personally believe there are 3 reasons that could lead to potentially increasing worldwide adoption of cryptocurrency:
- A Better redistribution of money;
- Standardized multisig/escrow contracts.
If you think I forgot about scalability, transaction fees or block size, please rest assured I havent. To me those arent real problems; as the network grows in security (more miners), user adoption and developer community, I believe we will see those issues getting resolved. Some others will appear, of course, but thats the nature of innovation.