So in the recent dragon tournament the winner points for global was over 23000 points.  I have a few assumptions that could be wrong because I’m not high enough level yet.  1 that a 6* legendary gets you 25points 2 that it costs 16 energy to do the highest level.  With these assumptions it would take 920 attempts with a 6* legendary every drop or 14731 energy now assuming you are getting these drops why would you need the rewards and waste your time going after them?