If the market says it is valuable then it is. The question is how long the market will say that. But you are right, if a consensus forms that it delivers on what it is supposed to then it will have long term value.
I'm all in on Steem but I don't believe there will ever be one crypto to rule them all.
In actuality a blockchain is just a network (electronic system used for the transfer of information). We all use thousands of networks and this isn't likely to change. We have our preferences but when we want to get something done any usable network will do.
I do think a viable use case for Rai might be IOT as you mentioned. There is no reason iOta has to own that market.