The Senate is holding pro forma sessions every few days during the break to prevent Obama from making a recess appointment to SCOTUS
The concept of "recess appointments" seems really shady. Did they have a decent purpose in the past? Seem like more of an abuse tool today
They have been around since the early days of the republic. Recall that, back in the day, it would take several days or weeks of travel for members of Congress to go "home" and come back to DC. During those recesses, sometimes appointments need to be made to continue the business of gov't. It made sense to allow time-limited appointments.
In the modern era, they are a way to kick the advice-and-consent can down the road.