Pneumatic Tools vs. Hydraulic Tools

Is this a trick question?

Air versus oil.

Can you compress air?

Can you compress oil?

Usually the pneumatic tools are impact type, the hydraulic are non-impact.

If you're referring to pneumatic or hydraulic torque tools, either can be "non-impact". Pneumatic torque wrenches exist whereby the output torque is controlled by the input air pressure.

Pneumatic torque wrenches are continuous-rotating whereas hydraulic torque wrenches are, for the most part, ratcheting.

A hydraulic torque wrench delivers much higher torque output than a pneumatic torque wrench of similar size and weight.

Hydraulic torque wrenches require an external hydraulic pump while pneumatic torque wrenches can be operated by simply plugging in to a properly conditioned plant air supply.

Hydraulic torque wrenches are much more robust and forgiving than pneumatic torque wrenches.

BoltIntegrity

What does it mean when you say more "forgiving"?

I want to consider the construction of the backhoe loader's "arm". In such a case, what differences (advantages and disadvantages) would exist in using pneumatic pistons in place of hydraulic pistons? I want to create a model of such a thing, using pneumatic pistons instead of the actual hydraulic pistons. I am not a mechanical engineer. If anyone can put this to me simple, I would appreciate it. I understand the basic principle of pneumatic/hydraulic systems which multiply the force by trading them for distance moved - much like other "simple machines".