This is all SE's fault and started with Final Fantasy 1. You think I want to sit there and buy 99 potions? Hell no, I got a NES Advantage and put it on turbo, and then took a C Clamp and held that button down. Go eat some lunch and BAM 99 potions baby!

But as long as it's more than 20-30 synths as others have said it'll be OK. This won't affect leves either because the recipe will be different for each one. Now if you're sitting there turbo'ing 100 grind synths of the same thing then yes, this will affect you. But after the recipe changes it's actually more beneficial to me to do leves vs. grind synths. You have to make more items now since the yields are lower (ex linen yarn yield is 3 yarn per 6 flax now), and leves are free mats + shards/crystals. This won't hurt anyone who's legitimately crafting.