There is an existing challenge Is it a completely even number? which is very similar to Powers of 2, but asks for 1 to be excluded. I think it's a good challenge, and some people agree, but enough people disagree that it's been unable to get far into the positive-vote range (it only managed to get as far as +3). Before I answered it and edited it, it was in the negative (-3).
My comment This would be a good challenge if there were also a "Powers of 2" challenge has gotten 4 upvotes. This seems to be a pretty clear message that such a new challenge should be created. But I am afraid of trying, because CGCC has a history of challenges being closed as duplicates for being far less similar to another than "Powers of 2" would be to this one. So it's a Catch-22.
However, there is precedent for very similar questions being allowed to stay up. For example, The vanilla factorial challenge.
So, can we do this for Powers of 2?
I would leave my own answers to "Completely even" unchanged, and wouldn't answer Powers of 2 myself, because my answers already compare and contrast solutions for that challenge with those for Powers of 2. But the vast majority of answers do not do this, even though I put a message encouraging it in "Completely even". Thus, if a "Powers of 2" question were allowed to stay up, I would edit "Completely even" to remove the clause encouraging answers to discuss their difference from Powers of 2.