I like that the lightsaber colors mean something. Color theory ftw. It allows you to play around with motifs and symbolism.

The Sith bleeding their crystals is so much better. It’s symbolic of their nature and relationship with the Force.
Not only do they have to steal a crystal from a Jedi (a test of their “survival of the fittest” ideology; if you’re too weak to beat a Jedi, you can’t be a Sith), but they also force the crystal to submit to their will, their dark side emotions. That’s what they do to the Force and the entire galaxy: bend it to fit their selfish desires.

When Vader bleeds his own crystal, it’s symbolic of his entire nature as a Sith Lord. He imprisons it within his unyielding robotic fists and subjects it to his power-hunger, his rage.
It’s visual storytelling for how can’t let go of his ego and hatred, because otherwise he’d have to face his guilt, regret, and he refuses to feel that vulnerability. He can’t confront it because he can never bring himself to believe he deserves redemption.
To make himself feel powerful, he makes others suffer.

It feels true to the original trilogy. It’s mythic, spiritual, fantastical, symbolic, fueled by emotion and character-work. The crystals being synthetic feels too prequel-like: overly complicated and based in mechanics rather then spirituality and emotional storytelling.