Most of the current 'use cases' are indeed horseshit. I don't think anyone outside of a few nutters cares about decentralised file storage or dog walking ICOs. I'm pretty confident not one single project built on top of the base layers that's around now will be around in five years.
However this very moment today try sending some money from your bank in Denver to a holiday rental in Sumatra and see how long that takes, how much that costs and whether it'll ever bother to arrive. There is so little comparison to Bitcoin it's pitiful and it's genuinely bizarre that it's still considered acceptable in these fast paced times.
As for other applications I think overall we'll see a curve of actual usage very similar to the dotcom bubble. No one'll know what to do with it. They'll drive prices sky high anyway. It'll collapse. Someone will figure out what to do with it and then it'll take over the world.
The most compelling uses probably still haven't been conceived yet.
Just purely based on speculation... I can imagine that decentralized apps, better yet just the ability to have contracts be created on the blockchain in a decentralized matter, will be purely beneficial to business at first with very niche needs; as it was with the very early days of the internet.
I really think decentralized contracts/apps will become beneficial to the average person, but I think it will be quite a long time before people actually work and create their own things on the blockchain. Regular people tend to flock to centralized businesses as of right now... there will have to be a huge change of mentality of everybody to actually take matters in their own hands and be responsible for themselves rather than having the crutch that is
"customer service"