No way would I want those stored in the browser.
Because then all it would take is a data thief to clean one out is the CC or Debit card number, with a fund transfer. This is one of the reasons why I boot with a finalized DVD, either -R or +R, not RW, as these can be written to, plus no USB stick, to perform secure purchases. Nothing is saved to disk & the reboot will flush the entire session, one can do this even on a very Malware infested PC & it cannot access the memory while running a LIve OS.
Am not saying it's a good thing to do, on an infected computer, yet if one suspects their install is infected, why take chances when one needs to perform a transaction? The bootable DVD is perfect for the job, and the US Air Force also has a bootable Linux that fits on a CD for this purpose, secret & secure communication.
Link Removed
There are release notes & how to's on using this, one of the main ones, is after browsing, if have done so, is reboot to perform secure transactions. If desired, one can remove the HDD, or disconnect on a desktop PC, though this is more for peace of mind than anything, haven't heard of anyone reporting their credentials stolen while running the distro. It's small & therefore should download faster than the latest Linux Mint or Ubuntu, and updated quarterly.
If the distro maintained by the military is good enough to assist in protecting our homeland, I trust it also.
Cat