i agree, that is an inadvertently misleading comment that he forgot to elaborate on. Just like chinese jujubes when grown from seed, random indian jujubes grown from seed end up being used as rootstock if the fruits turn out to be inferior. Or used as rootstock straightaway even before they start fruiting as jujus can be difficult to strike from cuttings(indian jujus are a little easier though compared to chinese jujus in humid conditions), so good quality cultivars have to be grafted to random rootstock.
indian jujubes can also have varying leaf-sizes just like chinese jujus, below is a video of indian jujube with larger foliage that presents like an R4T3 chinese jujube.
among chinese jujubes the cultivars li, sherwood, GA-866 have subtantially larger leaves, and likewise have larger fruits, ranging from round, to pear-shaped, to heart-shaped/chicken egg shape
indian jujube fruits will also present with said shapes and sizes, depending on variety
