Good question. I chose it initially because it was open source and way easier (in my eyes) than Apache. I don’t recall the others being an option at the time, or I was not aware of them. nginx does what I need without complaint, so I haven’t switched.
The only time I’ve willingly used a banking app is when they lock out my VPN IP. In those cases the app still usually works for whatever reason. So far, I haven’t found any functionality missing from the webapp, but I’m also dealing with brick and mortar institutions.
I would be concerned as they will eventually probably move to a phone app first ecosystem, however it will probably take a while. Some people are still only using in person and phone banking (where you call them and punch in numbers).