I dunno about you but my browser can hardly remember what happened last time I opened it let alone take care of my money. The web browser is the most monstrously complex application in the universe. It is only exceeded by the complexity of an NPM build.

If the signing device is separate from the browser, or better, separate from the PC, then browser security flaws are not as devastating.

Dedicated apps are always better. A lot of them are actually just dedicated web browsers too.