You may not have to have a return to zero complication, alhtough I really like that, but when setting for accuracy and timing it is a must, at least for me.
Does it really hurt the overall functionality of the watch? I have not seen it, although I dont have any really complicated time pieces. I admire AL&S and they have invested a lot of thought into stoping that balance, like on their Tourbillons that can be stopped at any position.
Really why wouldnt you want that? So much money is spent on accurate watches, what is the fun of that if not able to test that. I know you can test without it with simple math, but I like pushing in that crown right when the new minute starts. At least for me, I will take the stop seconds anyday.