There are two ways to get rhizomes. Most rhizomes are simply root segments, but you can bury bines in the Fall and they will put out roots in the Spring. If they only ship root segments that have started sprouting, that's a plus.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk