Usually, against a Norse player, phoenixes can be the battle clencher to win you the games.
The only counter they've got to the phoenixes are TAs, ranged MUs, and ranged buildings.
And because of the TAs' low range, axemen, CAs and slingers can eat them up while you take your phoenixes to the back of your army to be healed by the priests.
I use probably use Phoenixes more than Sphinxes or Anubites because they're so useful.
Send in one phoenix to your enemy's base, invoke meteor and BOOM. When that phoenix dies to TC or Hillfort fire, create another phoenix from the egg to finish off any buildings that weren't destroyed by meteor.