2005 Honda CRV Honda special Transmission fluid

To save money I have been trying to do my tune ups as thrify as possible without skimping of course on necessary things.
Honda's owner manual really stresses the importance of using Honda oil, transmission fluid, and other needed fluids.
I called and talked to someone in the service dept. He said I could get away with using other brands with most with the exception of the transmission, he said he could almost promise me that my transmission would blow ( not sure of the exact words) if I did not use
Honda transmission fluid.
So, how true is it of these car companies that INSIST that if you do not use Honda or Toyota fluids when replacing you will surely pay the consequences.
Just curious.
Thanks
Nancy