I wanna know this too
iirc, mala beads need to be "activated" and "charged" based on the wearer's energy. there are also a lot of rules when wearing it during prayers that would essentially inactivate it and you have to start the prayer all over again.
since she was consistently charging the beads (by meditating everyday), it's storing her energy, which is already strong enough to protect the emperor against the spirits (which is also the reason why you can't simply lend/borrow mala beads bc energy gets transferred from the wearer). not sure on the denomination but in some, you also have to chant a prayer when making/attaching every bead
Is there a reason she didn’t make a bead bracelet for the king too? Does it only work when she wears it?