I don't think it matters a ton either way, especially if fermentation is done.
If you worry about wasting a ton of energy/effort on keeping it a bit cooler, I would say let it warm up to 70. Cooler temperatures are always better for beer storage, but honestly a 2 degree difference won't be noticeable. You'll lose a very tiny CO2 out of solution at warmer temperatures, and will get slightly different calculations on priming sugar as a result, but I think it's really negligible to the point where I wouldn't worry about it. You might get some noticeable differences if it's not fermented completely, but this late in fermentation I don't think it will be an issue.
So yeah, there are some technicalities where you could make an argument for keeping it cooler, but at the homebrew scale and given the 2 degree difference you're talking about, I don't see any reason in terms of beer quality to choose one or the other.