There's been some speculation that marcescence may actually provide competitive benefits to the tree on a few different levels, including by insulating young growth against extreme cold in the winter and then deterring animals from eating new buds in the spring. Potential snow/ice stress is an issue in the early cold season, but since the tissue connecting the leaves gets progressively more brittle as time goes on, any remaining old leaves will simply get pushed off by the new ones as they unfurl. The bigger concern may be the long-term health of trees subjected to freezes occurring early or abrupt enough to disrupt their normal cycles.