Couples could be together much faster, which is important to many. I also know people who went to the US on a fiance visa and then was able to get a work permit fairly quickly. The difference in fees is minuscule.
I do agree that we don't know what the K1 will look like in Trump's second term. In all likelihood, it will simply get much slower, but CR1/IR1 will also get much slower. K1s are averaging around 5-6 months total, while CR1/IR1 are averaging 15.5 months (and getting worse by the month) even without Trump in office.
If I were applying today, I would go the K1 route for sure.