As to using the keyboard. When in Linux (as I am now) there are some mouse features that for some reason just don't work (will not go into them at this point), so the keyboard navigation features are a must.
Don't forget that Linux GUIs use the Mouse Wheel button for some Copy/Move/Paste operations.
You can automatically Paste highlighted text, using the Mouse Wheel button.
Dragging and Dropping using the Mouse Wheel button brings up an options menu.
Why would somebody not want to use Metro Internet Explorer for online banking, a new shopping facebook etc. If it's safer than the desktop Internet Explorer?
Maybe because of its upside-down layout?
If you really want to be safe use a Live Linux CD/DVD (assuming you have checked it for rogue items).
Nothing is going to get (permanently) written to the OS if you use a CD/DVD ROM.
"Nasties" could get into your RAM though.
Obviously you shouldn't surf the Internet before you visit the Bank.