Certainly your opinion, but hear the opinion of others too. My bank has been repeatedly asked by regulators to show evidence of customer education on scams and risks. Especially timely messages on current scams or P2P money scams. They are implying the bank has a responsibility to educate customers on ways to safeguard themselves. Even regulators have mentioned email campaigns to existing customers.
As a consumer, not banker, I receive those exact same type of emails from banks and credit unions my family work with that the OP is referencing. Additionally, one of those banks sends communications about upcoming federal holidays and how that may impact me as a consumer.
Back to my banker life, those communications have the potential to be helpful to what the OP is asking on. Have you ever talked to a contact center on the business day after a holiday? Even with other prompts in place for call flows and web banner messages, our contact center still gets an influx of users trying to connect with the bank on holidays.
Consumers are inundated with [censored], no lie about that, but that's because they've often signed up for accounts and agreed to receive communications during the enrollment. I'm guilty as charged and if it's not something I want, unsubscribe I go.
OP never talked about the emails being unsolicited or even the process of a customer agreeing to receive them FWIW