[TheForge] bandsaw design question

[Bruce Freeman]

This recent thread on bandsaws made me wonder about the mechanism for
lowering the saw against the material.  I've seen pneumatic devices.  I
understand some sort of springs may be used.  

However, wouldn't it  make more sense simply to balance the weight of
the saw with a counterbalancing arm?  Then weights could be removed
corresponding to the amount of pressure you want to exert on the piece
being cut.

Is such a device in use on any saws?  If not, why not?  Am I missing
something?

Bruce
NJ