When does matter and antimatter not matter?

When we are dealing with a particle that’s its own antiparticle, or so it would seem. And now that physicists have succeeded in creating the Majorana fermion, such a particle can and does exist. What do you think of this? What might it mean for quantum computing?

Is this a definitive answer to @talljasperman‘s question, “If Matter is +1 and Antimatter is -1 then what would 0 be?”