What's going to cause consumers to want to use BTC?
The million dollar question. Most of the incentive is for merchants. 90% of it.
Some incentives which may motivate consumers in the future:
1) Slightly discounted prices offered by merchants that save money on merchant fees.
2) Bitcoin being offered as a salary option from employers.
3) Bitcoin being included in retirement and pension funds as an option.
4) The biggest in my opinion: Press and Economists finally acknowledging that Bitcoin will increase in value over time. General awareness of this. Financial advisers mentioning it to clients. Its deflationary aspect I believe will be its biggest incentive for consumer acquisitions. But getting to this stage, where its a "well known fact" and mentioned repeatedly on television and news articles, is going to be awhile.
In the end, people will buy bitcoin, and then subsequently spend bitcoin because the longer they hold it, the more it is worth. Many will see the small gains, and think: "I can spend some of that now, because the rest that im holding, will continue to increase in value". This encourages commerce.
If you know your $10,000 worth of Bitcoin holdings today will be worth $13,000 in a year, you'll freely spend $2,000 of that on a vacation. And all you have to do is wait another year to get another free vacation. Bitcoin is a savings account with interest, among a million other things. There will also be 3rd party services that will create incentives as part of their product offerings, I believe. The volatile fluctuations will decrease, and a very slow, creeping-upward in price will be the new norm.
-B-