IOTA isn't designed to be a currency per say. Their team suck at designing a user-friendly wallet, because they are mainly engineers and mathematicians who are focusing on the IoT aspect of the technology.
But on the front of adoption in real-world IoT use-cases, IOTA is actually making very impressive progress!


If you want a coin that has zero fees and fast transaction that is designed to function as a currency coin only (and nothing more), then go for Nano; which its aim is to compete with BTC but cannot be used as a IoT bridge like IOTA is designed for.