I really don't know if i shall. And this time I'm really asking for your opinion on that, just leave a comment. A Pro is that many users in corporate environments are still forced to use our favourite old-school browsing grandpa. And excluding a mentionable amount of users just for the sake of less work?
On the other hand, I guess that most people using really modern WebApps are nevertheless forced to use modern browsers. I don't know, really not. A short yet true list of cons is presented here as well, and a rather radical point of view presented by nick cowie.