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.
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 👍