This was essentially a day for students to work on U2 WS4 in groups. It allowed my 5th & 6th Hours to catch up with my 2nd hour so that we'd all be on pace for Friday's Unit 2 Assessment.
The main problem with allowing students time in class to work is how many of them will waste the time thinking that they "get it." This means they're not prepared to be productive in a class discussion the following day and they don't have any notes to use as a reference on open note quizzes. By the time feedback from the quiz arrives to indicate that they do not in fact "get it," they're short on time to fill in the gaps before a formative assessment.
The related issue there is how many students simply refuse to think through problems on their own, and demand step-by-step instruction on every problem before they'll even take an assessment seriously.