The Interstate Highway System, manned spaceflight, and National Parks come to mind.
Conservation of land is a national priority. As such, no state or private entity should be entrusted or made to be solely responsible for the upkeep and management of said valuable resource for all the people. That's why Yosemite Valley's management was transferred from the State of California to the Federal Government.
As Wallace Stegner said, "National Parks were the best idea we ever had. Absolutely American, absolutely democratic, they reflect us at our best rather than our worst." (Except for that whole disinheriting the native peoples of their own lands thing... but definitely American...)
The argument isn’t “we can do a better job than you” it’s “we are allowed to do this job for you”. Whether they can do it better is irrelevant.
As an aside, if we are looking as a whole, the federal government generally can and does do everything that they do better than the states could do it.