I don't actually think Butler should get blamed for taking that. For one, it was an open look. Two, lets be honest Butler was the only reason Miami nearly won that series especially with how he played the last two games. Everyone else was either super inconsistent or struggling with their shot. If Butler settled it, Boston then comes back on defense and gets set and you're not guaranteed to score there either even if you "settle it".
Now one thing maybe Butler could have done was keep going and try to drive. Horford was on him but no one else was behind Al. Even if he gets stopped he may have been able to at least draw a foul. Tatum and Brown were close but no guarantees they'd be able to come close the gap in time either.