There's a little theory I have that's basically trellium inverts a metal's ability making it have an opposite effect, giving the opposite allomantic ability and absorbing the opposite Feruchemical attribute like Trellium hacked gold absorbing injury rather than health. I think that by hacking lerasium hemalurgy, whatever metal can be used to steal 'all abilities', with trellium it makes one immune to hemalurgy so that no one can remove powers from you.