We have Amazon fire tablets for the kids. They work very well for consuming media from the Amazon ecosystem.
Problem with iPads is the cost. Problem with Androids is the variety and different specs to choose from.
That sort of price is also cheap Windows laptop/tablet convertible territory. You can use it as a tablet, but then stick the keyboard on if you need it. Like a Surface but loads cheaper and not quite as good obvs.
Re online banking etc – you can only install apps from Amazon on a Fire. They do have a lot of apps, but they might not have your online banking app. Websites would still work, but the apps are better.