The bottom line: use isobaric when it makes sense. If you already have the drivers (like I do) and are willing to use two in order to cut the box volume in half.
Unstated in the video is how important box volume is for speaker design. The box volume determines the tuning and how flat and extended the frequency response will be. Therefore, putting a driver that's designed for a 200 liter box in a 100 liter box will give you a very poor response. Being able to cut that box volume down to something more acceptable is the key reason to use two woofers in an isobaric arrangement.
Regarding efficiency and power, isobaric reduces efficiency by 3db, but the more modern woofers that are designed to work in small boxes have that efficiency drop built in - there's ALWAYS a tradeoff - no free lunch - to get more of what you want, you have to give up something to "pay" for it. For isobaric, it's a drop in sensitivity for a reduction in box volume.
That drop can be regained by wiring the drivers in parallel, but then you need twice the power to get the same spl. While that sounds like a major drawback, increased power requirement translates to increased power handling as well, so possibly a slight advantage for something like a subwoofer.
Also amplifier power is cheap today.
I know, I'm using the terms "sensitivity" and "efficiency" interchangeably. There's a difference, but not one that really makes a difference for a casual talk like I did here. Focus on what's important instead of searching for details to nitpick about.

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