What's the best choice of word for an action/activity that has no benefit (i.e., strictly speaking, "unnecessary") when trying to put emphasis on the fact that the action is, in itself, wasted?
Saying "wasteful" is also technically correct because some time/effort is "wasted" on the part of whoever is taking the action, but it might give the impression that it is causing waste externally (general resources / the environment), when, in fact, it makes no difference.
Consider this example: some people argue that DST (daylight saving time) saves electricity for lights, while others argue that it causes more energy/resources to be wasted due to use of air-conditioners, disruptions etc. (it's an example, so please don't start a debate on this here!). Some studies on this have found pros and cons in different areas that probably offset each other, so the overall benefits of either case are inconclusive and probably marginal.
To me, that sounds like switching times is unnecessary in that it has no overall effect/benefit, but "unnecessary" sounds a bit too neutral (doesn't matter, so couldn't care either way); I actually think that going through the process of switching (which is not trivial) is a wasted effort, but calling it "wasteful" might give the impression that I espouse the opinion that DST has overall adverse external effects (wasted energy for ACs/heating, losses in economic activity etc.), which is currently not supported by evidence. In other words, I want to express that I see the main "waste" to be the activity itself.
