i think trying to kill the hydra early just to get this is not worth it, if you level up int a little bit your normal catalyst will be just as good, doing the hydra is way more difficult than killing taurus demon in my opinion, he literally gets staggered after 2 heavy soul arrows, which you can buy at the start of the game, you can kill him before he even gets close enough to hit you, the hydra on the other hand will murder you. (and the crystal golems will too, they hardly take damage from spells, your best bet is to let the hydra kill them for you, but either way this is still way more difficult than going with the intended route.) and dont get me started on the gold golem too, you need the reinforced club to deal any damage to him, at that point if you are already there, you might as well continue in that direction instead, the time you lose for this huge backtrack more than makes up for the potential gain from having this and dusk crown.