That's a lie. Banking apps work fine on desktop browsers with dedicated security tokens such as smart cards or code displays. My banking app runs on GrapheneOS, but my national identity app which it uses for authorization and authentication doesn't. Luckily the national identity supports hardware tokens, so it just means I have to scan an NFC token in my pocket instead of scanning my fingerprint in the identity app.

Banking apps also work fine on rooted phones which mask most common "detect root" schemes. Don't install sudo for instance, my banking app barked when I did that, removed it and it was fine again (they use the cheap package from one of the many obfuscation firms)