The Time Spiral block had a time theme, with the three sets representing the past, present (okay, alternative-reality present), and future
The key difference is that they lack basic land types (a relevant change for any format with Fetch lands), and that they enter the battlefield tapped unless you control two or more of any other land, not just basic lands, but they are also only be available in allied color pairs
None of the tapping requires mana or tapping her, so you can do them on arrival to the battlefield and as many times as you have untapped stuff
These codes will often reward you with a card style, which is a skin of sorts for specific cards, or artwork for sleeves, so you can make your deck look a bit fancier
As much as it's going to be a major advantage that full copies of Swords to PlowsharesSwords to Plowshares probably ends with someone having an insane life total, it's nothing compared to the eight lands full copies of Path would result in
He said maybe in the future last time I checked
