His NFL experience? He had 7 carries for 24 yards in 2020 and sat out the entire 2021 season. As for what he's always been, that's just a guy who edged out some other not particularly special guys to get the 3rd RB spot, which is no different than Davis is trying to do now. As for special teams, he has one solo tackle and assisted on 3 others.
None of this suggests the kind of experience the Cowboys will feel they can't afford to lose or that someone else can't replace or exceed.
All this said, I'm not saying Davis will beat out Dowdle. All I've said is Davis has looked better than Dowdle this preseason. Yes, there can be other factors - the uncertainty of the players these guys are playing with and competing against makes preseason hard to judge by.
As for the QB commentary, which, by the way, has nothing to do with what we were talking about, your take on QB2 not mattering has a very notable flaw. While it's true that if Dak gets hurt and is out the rest of the season neither Grier or Rush is likely to have big playoff success, you are ignoring the reality that an injury to Dak may not be season ending. What if the Cowboys are doing well in the division and Dak were to miss 2-5 games? In that case having a QB that can just win 1-2 games could be the difference between making the playoffs or not, and Dak could be back before the playoffs.
The same applies to backup at RB. If Zeke or Pollard goes down we won't even need RB3 to take a major role. Just spelling whichever is left will do the job. And, again, suppose Zeke or Pollard are only out for a few games and the team just needs help getting through those games?