Why would people want to exchange their bitcoin for fiat in the first place? That is the main problem that should be first addressed to answer your question. Instead of building a circular economy based on bitcoin, in which people will never again have a need for fiat on/off ramps, they still are trying to exchange a more reliable currency for a less reliable one. I see no reason for doing that, except for them seeking short-term profits or maybe there is the absence of necessary infrastructure or legislation to spend bitcoin directly on the things they need. Anyway, bitcoin is not battling with banks per se, it is meant to replace a flawed and obsolete system of central banks, which is, by meddling with money, artificially causing inflation, cantillionism, and other terrible things that make the poor poorer and the rich even richer. When this system is finally replaced, and we switch to bitcoin, banks will be more competitive and, therefore, more cautious about giving loans that may end up unproductive and cause bankruptcy.