If I was part of the Harris/Walz strategy team, this focus on Walz' military service is the exact thing I'd want to keep the conservative news cycle focused on.
Why? Because the #normies don't give a shit about it. This isn't 2004 when the country was still riding the 9/11 Patriotism and OIF invasion trains. There's not going to be a "Swift Boat Veterans" event that harms Walz.
The undecided, nonmilitary voter isn't going to look at the intricacies of his rank, or understand his 24 years equates to less than 1k days like
@amlove21 mathed out.
They'll just be between the conservative "Walz abandoned his unit" and the liberal "Bone spurs" or "Attacking war hero John McCain" (irony in the making).
The longer spent on Walz and his record is less time spent on policies. Again using
@amlove21, I think he's the only person I've seen in this thread so far specifically bring up the MN abortion laws.
I might not agree with his take, but it's a least a policy point you could actually move voters with. The less time conservatives spend on that increase the chances the DNC sneaks out another win.