Depends on the duration and context, but for normal business travel, coursing etc yes. The NJCC travel directives are pretty straightforward, no reason to screw people to save a few bucks, especially when millions in travel gets returned every year.
We already have retention issues, that kind of thing is another one of the thousand cuts (especially when you are with on TD with civilians who would get a normal hotel).
We invest a lot into training people and pay well enough that it would be a 'penny wise, pound foolish' situation.
Saying this as it was actually a COA for ships doing an out of area refit in Port Weller, where they wanted to put the crew up in a local armoury for a few months. After working long days away from home that would have been a huge disatisfier. Fortunately that was a case where 'quality of life' actually made a real difference, and they got set up in a bare bones but clean motel. We were spending $28M on the project; the accommodations weren't even a rounding error and were already assumed. It wasn't free either, we would have needed some extra reservists around to get in/out anyway, and would have screwed up their training anyway.
Staying in the shacks isn't so bad, but sleeping on a cot in a gym for no good reason is bullshit.