The Fifth Doctors single ability is Peaceful Coexistence, which at the beginning of your end step, you get to put a +1/+1 counter on each creature you control that didnt attack this turn, or that didnt enter the battlefield this turn
If the equipped card is a dork it gets +2/+1, so it has synergy with artifacts that can become dorks like vehicles and Guardian Idol
Salvation Colossus wants to be milled, which isnt always easy in energy decks, while Liberty Prime, Recharged is a potential Jeskai commander if you just like big giant robots a lot
The set had a limited print run and printed the card as a Mythic Rare, so it was still by no means the easiest card in the world to obtain, but it still made the card astronomically easier to acquire than it ever had been before
Playing lands is pretty much nonoptional even the Oops, All Spells decks run lands in the form of MDFCs
If you attach a Water Energy to Totodile, for example, it will only let you perform its first attack