On the subject of transmission fluid, what are the opinions on using "Universal Hydraulic Fluid"?

Several years ago, sometime mid 90's. I had a transmission cooler line fail, and literally pumped all my fluid out down the road.

I was stuck on the side of a county road, and a farmer happened by, we towed the car back to his place via tractor. And I repaired the line with some hose I kept in the emergency kit.

I now needed to get fluid in the transmission. The farmer had no transmission fluid, but did have TSC brand jugs of Universal Hydraulic Fluid.

I got the gears turning in my head, and know that some hydraulic systems uses transmission fluid, and the transmission is basically a hydraulic pump, so I added the Universal Fluid to the 727.

It worked, and worked well. In fact because I was on such a tight budget at the time, and it was my "beater" car. I never changed it back to transmission fluid.

I had the car for 4 or 5 more years, and even made a cross country road trip from Eastern Nebraska, to Western Wyoming. Never an issue or slip.

So what say the transmission builders? Was this a fluke of luck, or is there some merit to using something other than "transmission" fluid.