Argument against, if you have a strong OL or strong rushing scheme, drafting a high rb could pay huge dividends. We saw Zeke get drafted when we had an elite line and he lead us to the #1 seed with a rookie QB and a below average defense. Cleary, Cowboys do not have an elite OL or scheme.
The counter-argument Jeanty plays with a poor OL at Boise, he can make an average line look far more better then they actually are.
I am not opposed to taking a 1st rd rb if he is the best player on your board. They had Dalvin Cook rated higher then Taco and drafted for need.
What happens if he becomes the next Sanders, LT or Peterson, you would make the same mistake the Packers did when they passed on Barry?