Researching work benches will often show many examples of the sliding deadman. I opted not to put one on my bench because I valued drawer space more.
On the rare occasion when I need to support a piece from the bottom I'll just use a clamp in expansion mode.
Good for you I guess, but I value the space under my bench and so I would never put drawers there. The bench is for clamping things to, and often that means taking the clamp apart and reassembling with half on each side.
For sure, clamps are important! There's a gap between the top of the cabinet and the underside of the bench.
I will admit though that's it's sometimes necessary to position the clamp with the bar extending below the surface - in that case not having drawers would be best ๐