Halfway through right now. Quite interesting, learning about east coast vs. West coast sound design philosophies and how that shaped the products we know and use. Then veers into some fairly niche territory. Makes me want to buy a bunch of colorful patch cords and start my own modular system.

Was it worth watching? I thought it was strictly about synthesizers?

Yes it is entirely about synthesizers which to me is well worth watching. Focused on Modula synths, so if that's not interesting to you, you will be bored.