Ok, he had two good seasons -- in both of which he played fewer than 70 games. In general, I'm not terribly impressed by players that need 37-39. So sure, fine, he won't turn back into a pumpkin.
Even so, and even acknowledging that he's a pretty good two-way player, his scoring prowess is vastly overrated. He has one good season at 18 pp36, and one at 20 pp36. For comparison Crowder scored 16 pp36 last season, and Bradley has averaged about 16.5 pp36 over the last three season. No-one is confusing these guys for any sort of major scorers. Someone like Isaiah Thomas is a scorer (25 pp36 in Celtics uniform). Meh.
I just want to point out that it's irrelevant to the discussion at hand how highly exactly you rate Butler. If there were discussions between the Bulls and the Celtics involving the 3rd pick, and regardless of the exact parameters, it is safe to assume such discussions did indeed take place, then it should be obvious that we were interested.
Trading your best player for three inferior players and no future draft considerations is a fantastic way to rebuild. This is nothing like trading the calcified remains of the players that were one Pierce and Garnett for multiple lottery picks in different drafts.
No, that is subjective at best, and nonsense at worst. Trades like these happen often enough because two teams go in different directions, and what constitutes as "value" depends on their respective situation.
From Ray Allen over Pau Gasol to Carmelo, there's a long history of all-stars traded for a bunch of "lesser" assets, especially if these assets include draft picks.
Besides, you can't call Butler untouchable in one post, and a pumpkin in the next.