I regret getting in the way of the OP's 15 seconds of notoriety, not to mention the stigma of discussing style rather than focusing on his scintillating content. But I do think you're missing something.

Certainly, bold, italic, and underline have their place. They are very useful tools. But what happens if someone copies your marked-up text from the screen and inserts it into some other context? Let's find out. I'm going to preview this post (to simulate the experience of someone reading it) and select the first sentence of this paragraph. Then I'll return to the edit box and copy it into this post as the next line:

Certainly, bold, italic, and underline have their place.

Hmm. Something's missing! By relying on markup codes, you are making it easy for someone to misquote you without intending to do so.

I may need to raise my voice just a little to express fully what I'm trying to say here:

Plain text DOES have its advantages, even on a "channel with greater capability".