Burn spells can help create a fast-paced game
Giver of Runes is the Modern-legal version of Mother of Runes (also called Mom), and its role is to protect a particular creature
Powerbalance checks off all the relevant boxes for me: its a callback to an awesome card from years past, it forces interaction (in other words, makes me have to pay attention to the game), it gives you free stuff, and it allows for fun top-deck manipulation
If they're twice as thick as a regular card, it would pretty much be a nonstarter if you planned to mix them with your other cards (like lands)
On top of all that, Mangara, the Diplomat has lifelink, making it a great creature if you need to stabilize from a disadvantageous position
Untap with him, however, and youre easily going to be taking over the game