No, just the "last mile" just before the DAC should be fibre. All the analog gremlins should not be able to travel in the glass fibre cable into your DAC.
Using all fibre would not hurt and maybe cheaper or easier. I do not know the costs. It is not something I am wanting to do but if I had the option, I likely would have chosen fibre.
I have Sonore Optical Rendu's for the final mile before the DACs. I used to own a Lumin X1 DAC that had a fibre input in the DAC. A great feature but I sold that DAC.
