Tesla Inc. has become the latest major corporation to make an investment in bitcoin, underscoring the increasing acceptability of the digital asset.The big question observers are asking is, why is the Elon Musk-run company doing this?Monday, electric-car maker Tesla said in a public filing that it purchased $1.5 billion of bitcoin and that it expects to begin accepting payment in the cryptocurrency for its products in the future.The move by Tesla to invest in bitcoins was seen as further confirm