I'm not sure what you mean. It's just the bank's website where one can log in and make transactions, such as paying or transferring funds or just checking transactions. My bank accounts and credit cards all have their own website, at least here in Australia.
Because some banking apps detect root even with magisk hide and consequently don't work, the alternative is to use their website to do transactions.
Yes! And that works fine with my bank. I downloaded a secondary browser to my Android device and set its User Agent string to "desktop". I use that browser for accessing my bank. I also changed the home page of that browser to be the bank's home page, and I even overrode that browser's desktop icon with the same icon that my bank's Android banking app uses, so it even looks like the standard banking app. I can perform any and all banking transactions via that web-based connection to my bank.
<opinionated-rant>
This whole thing about banks preventing rooted Android devices from performing certain functions is silly at best and (IMHO) massively stupid at worst. Our desktop machines (Windows, Linux, and Mac) are all "rooted" in the same way that Android can be rooted. In other words, on our desktop computers, we can (1) switch to "root" or "Administrator" any time we want, and (2) run programs in a rooted fashion via "sudo" or similar OS-specific software. Banks do not prevent us from accessing web-based banking functions via our "rooted" desktop computers, and so in my opinion, it makes no sense whatsoever for them to cripple their banking applications on "rooted" handheld devices. And actually, many more desktop computers get routinely hacked than hand-held devices, and banks don't seem to care at all, at least with regard to the use of their web-based banking software.
And as is discussed above, the banks can't stop us from fully accessing their banking software via web access on our Android devices -- including rooted devices -- and so whatever imagined security they want to have on handheld devices is non-existent.
Furthermore, I carry debit and credit cards in my wallet. Anyone could steal my wallet and thereby have the opportunity to hack my CC or bank accounts. Also, the businesses in which I use my debit or credit cards for purchases could have unscrupulous employees who steal the card numbers. My banks do not try to stop me from using debit or credit cards, even though they are even less secure than using a rooted Android device.
Therefore, the main result of crippled banking apps on rooted devices simply is more headaches for the users.
</opinionated-rant>