My thinking is the fruit may be challenged until the growth settles down. With a big established root and small top, bud or two from graft, the new growth will be vigorous. I think that's not favorable for fig quality. However with certain varieties, small fruit that shrivels as it ripens, I've had good fruit on vigorous trees. It's the big figs that tend to get watery that suffer from strong roots and vigorous growth, IME.