Phoenix Urigon readied "at the end of each turn"

[renew]

Phoenix Urigon is "readied at the end of each turn".
Apart from the turn during which it dies and comes back in play ablaze, why/where does the "each turn" matter?

edit: I can't reply to Veles' explanation, but I now understand. I didn't think about the case where the turn was the opponent's. Thanks!