Pneumatic actuators are relatively inexpensive, have a binary state that is easy to control, and offer a high power density.
Pneumatic systems often use small orifices and valves to control the air flow which would be quickly clogged by any debris, so cleanliness is important.
An aside: PID control was, back in the day, mostly implemented in pneumatic control systems (using a set of levers, bellows springs and nozzles). Pneumatic control systems were (and still are) used a LOT in industrial control systems where e.g. flammable environments where electrical equipment is too much of a risk.
https://control.com/textbook/closed-loop-control/pneumatic-p...
Pneumatic "muscle pressure" is common in lots of industrial applications, especially those that operate in austere environments. But those are different than the tech being researched in the article in large part because the mechanical compressors in industrial applications are hugely inefficient. Many constant volume compressors have 90%+ of the energy as waste heat.
I believe the article is referencing isobaric (constant pressure) compressed air energy storage (CAES) that have much better efficiencies.
Hydrostor has a thermal management system that captures the heat and stores is during compression. Then it reuses the heat when it is decompressing the air.[1]
This seem extremely promising as a much smaller footprint solution than pumped storage and much more sustainable and lower cost than any other energy storage solution. I just heard about them today, and I'm extremely impressed.
Think of a bag of air under water on the ocean floor. The height of the water column is (relatively) constant, so the pressure in the bag is also constant. The air is being compressed as it goes from sea level into the bag, but inside the bag, the pressure is always the same. If you define the system boundary as the bag, it's an isobaric system. The volume changes, but the pressure is constant. Contrast that to the compressor you might have in your garage where the rigid tank provides a constant volume, but the internal pressure changes.
For me, I like air powered tools because of their power and reliability. They'll almost always have more torque and power than similar electric tools.
When you start getting into 3/4 and 1" it's not even a comparison.
The cordless is nice to have but it's a luxury/convenience tool, not a replacement.
The web of tubes was for messaging. (Just like some bank drive-ins work.) Users would put paper messages in capsules which were put into a pipe. Compressed air would carry the message to a central switching station, where human operators would re-route the message to the proper destination tube.
It was pretty cool, in a steam-punk sort of way.
Lots of the mechanical automations inside some of those warehouses are powered by compressed air in open loop systems. As the conveyor pushes the item off, onto a different lane, there's a distinct hiss of air escaping. The movement of the machine was powered by compressed air.
Out in the parking lot in these facilities, you'll see a huge compressed air tank (or many), constantly being refilled. Tubes from these go into the building like arteries in a body. Often inside the building there will be buffer tanks to help ensure constant pressure.
Source: worked for a few years with guys who maintained these systems. Some of what I learned may be wrong, so feel free to correct me.