Blockchain technology will neither “replace” or “substitute” for existing banking systems, in my opinion. Blockchain technology is more likely to be used and integrated with current technologies by financial institutions that are interested in participating in the Industrial Revolution 4.0 by using tools like big data and automation to better serve their clients. drift hunters

A bit of tricky question Kris. From one angle, i feel that blockchain or crptocurrency by itself will not “replace” banks given that banks do not just serve a retail function, but it also serves a corporate function. Even with regards to retail banking, the blockchain or cryptocurrency is less likely to replace the monetary system given its volatility and at the moment the impediments to quick transactions (since it takes more than few minutes for a crypto transfer to be completed).
However, one thing for sure many banks are and should be incorporating the blockchain tech into its ecosystem and value chain. Given that features such as smart contracts etc. should complement a bank’s activities, I do see some potential for banks to incorporate these technologies and be more efficient. Given the “open source” feature of most of these technologies, it will be relatively cheaper for banks as well.
To summarize, I do personally feel that the blockchain technology out there will not “replace” or substitute traditional banks. Instead, banks looking into being part of the Industrial Revolution 4.0 with things like big data and automation is likely to adopt the blockchain technology and try to integrate it with their existing technologies to better serve its customers.