The majority of leagues are down to the final four teams in the postseason, so no more mad scramble to the waiver wire.
There are fewer owners vying for players, especially in leagues that only allow playoff teams to make additions.
Plus, the majority of your starting lineup is likely set by now. Still, injuries and other situations can always cause you to dip into your depth. In leagues with three wide receiver slots, your third starter may not be a sure thing. There are still existing and potential needs that will exist, so keep working the waiver wire.