All your reasons can be refuted by the simple fact that banks don't need the blockchain technology to do what you just enumerated. Everything from your list can be easily done with a distributed database or fail-safe filesystem (like what Google uses on their servers). But since they don't employ these tools (at least, en masse), it seems there is no particular reason or advantage to implement them. That is, their choice is toward further centralization. As I see it, blockchain is essentially about working in a trustless environment...
But the banking system itself is the opposite of that, since the Central bank is the ultimate arbiter and a source of trust by definition
when you realise that "blockchain" is just something like 5% of the security model of what bitcoin is.. you and i can both laugh at what purpose the banks are overselling the "database" 2.0 they are harping on about..
but what data they put within the database. and how they monetise it and how that data has its own utility.. is something only the banks will know.
eg health records, ID, births deaths and marriages, financial, produce and manufacturing tracking data.. the list can be endless. and monetised in endless ways. but that data is nothing to do with blockchain.. blockchain is just a small option for how that data is stored more efficiently then the old way databases worked
But I was asking specifically about the blockchain technology and its possible use by the banking sector, right?
Besides, I don't see how blockchain makes it more efficient to store, organize and process data. In every of these aspects, blockchain simply sucks, to be honest. If you need redundancy, there are special tools for doing just that. I can't possibly comprehend why you would try to use nodes for distributing your data (in search of redundancy or efficiency) which are in no way affiliated with you and don't have to keep your data in the first place. To organize your data, you use databases which specifically aim at fast retrieval of data entries in arbitrarily order (binary trees and that sort of things). The blockchain data format (JSON if I'm not mistaken) is simply unusable for these purposes. Processing data has nothing to do with blockchain altogether