Recently, I see so many emerging vendors that are advertising their use of zero-trust. What potential risks are we exposed to if we shift to zero-trust in our bank?
Zero trust tends to increase security. If done excessively, then security becomes excessive and that occurs at the expense of usability, as the two are often (though not always) inversely proportional to each other. Is it safe from a strict security standpoint? Absolutely, but it may not be what you want. If your goal is to avoid getting hacked (for example) and you succeed by having excessive security, it won't do you any good if it results in no one using your bank because it's so tedious to deal with.
Would, say, doing a strip search on customers entering bank premises increase security? Definitely! Will it result in you actually saving money because there are fewer incidents? No, because everyone will avoid your bank like the plague. You must find the proper balance between security and practicality. This is called risk assessment and must be done by any serious company that wants to succeed.
Honestly though? It seems like these vendors are just using the term as a meaningless buzzword.