You are 100% correct, they have a huge challenge in finding a use case.
Honestly this is one reason I'm defending their decision to distribute a large number of coins through a grant system. I can think of several uses like rewards-points that work if you have a large initial supply to give out promotionally, and if they are never used the value will slowly seep back in. One key to long term success will be to either have the project mine themselves, or cater in some way to the mining community to get the mining proceeds back into the non-mining community.
It's the same problem as coinage in England during the Industrial Revolution. Coins flowed to London and stayed there, and the country as a whole was suffering a lack of small change that resulted in private local currencies that pick up the slack. Currencies are mostly local in some way, I think FRC and other bitcoin forks are going to get drawn to a locality (either physical or online community type) or more and more localities will create their own cryptocurrancies. I don't think we are going to see a few BTC clones, I think we are going to see thousands of coins/notes/certificates/coupons/shares of every description.
I tend to agree that the grant system makes some sense given the barriers they otherwise face in getting people to actually use the coins. But the grant system kind of makes using bitcoin a strange choice. The usability issues in bitcoin are largely due to requirements imposed by being decentralised (e.g. waiting for confirmations, when a centralised system can immediately confirm). By having a large number of coins centrally controlled there's no way some of the main benefits of decentralisation can be achieved - everyone HAS to trust the body controlling those coins. So that body may as well be an issuing authority as well. But I guess miners etc aren't willing to pay fiat to buy coins from a central body - but will happily pay fiat for electricity and hardware to mine them for 'free' whilst a central body owns and controls a large chunk of extant coins without having 'paid' for them.
I do agree that we'll likely see thousands of different BTC-type block-chains for all manner of purposes. Well - we may not actually SEE them - as a lot will be for specific purposes only of interest to a very small group of people who want to track some specific right/ownership/entitlement in a semi-anonymous way without a central point of failure.