As someone who has lost many hours of my life 'watching' PP presentations, containing whizzing left/right/up/down clipart and cartoon images, big bold fonts (in every colour of the rainbow), jokey one-liners, this move would certainly get my vote. (Are you reading this Mr Cameron!)
When your less brave colleagues are patting you on the back for making a sale and you are thinking, "All I did was tell them we wanted the business, explain why we deserved it and ask them to give it to us! It's not rocket science!"
You have no control over your recipients company firewall/spam filters, which will pull out elements of your beautifully crafted html email, if that's the only version you create...
...it is possible to identify the specific impact of a spelling mistake (within your website) on sales.
All it takes is a room full of dedicated (really dedicated) people, intent on relieving organisations and individuals of personal/private/corporate information they can sell on the open market.