When a face up damage card is dealt, you can discard this card...

Does it mean discard the drawn damage card or discard Boba?

"This card" is used on ordnance, like Proton Torpedoes, which makes me believe we are to discard the Boba crew card.

Did I read it correctly?

You discard Boba in order to choose and discard one of the defender's Upgrade cards. He's a one-shot use.

You discard Boba, the damage card stays put.

Great, I haven't lost my reading skills completely then.

Once Boba gets his man (or woman, or item of interest) his job is done and he's off to the next job.

That's mercs for you...

I do like the idea of him taking out Palpatine, though. A 1-point bounty hunter that can eliminate a powerful 8-point Sith Lord. Good value in my book.

He's the "8 minute total screentime; incredibly popular nonetheless hero" of Star Wars. There's nothing Boba can't do.