I think the main drawback is that it's simply more work.I have 10 pounds of apples I plan on using a food mill to remove seeds tomorrow. I don't see anyone mentioning using a food mill, is there some kind of drawback to using one?
My pear and crab apple this year were fermented with the pulp and seeds. My apples are crushed and pressed but I'd like to ferment with the pulp just out of curiosity.
Lots of opinions about using/not using seeds. Personally I think the seeds are hardy and won't affect anything by a 5ish day ferment - but I don't have scientific proof.