Maybe if the blue decks really end up being about tempo and pushing damage I will change my mind
Considering it only costs one mana and has two toughness, it's no surprise it is worthy of its value when combined with foil, retro borders, and is only one of 500.
Narset, Jeskai Waymaster Narset, Jeskai Waymaster gives you an explosive draw option at the end of your turnif you're willing to let go of your hand
Caves of Chaos Adventurer takes the initiative when it enters the battlefield, and with trample, it can easily take it back should your opponent deal damage to you
The problem is that it's very easy to blink Miner over and over again, but there aren't very many support cards you can find room for in an energy deck that care about it
A lot of the coloured cards you play are things you play at the end of your curve and so the burst this offers typically isn't useful