The five-mana commanders instead focus more on ramp on turn three, which can often accrue more value than spells that cost less, but still help with the game plan of getting a commander into play a turn early
1-4 cards of rarity Rare of higher
Now, WotC can try to push the Winter set up in the calendar all they want, but eventually it runs up against their holiday break, which is built around Christmas, and Christmas does not move
This is probably the way to use Nuclear Fallout, but wiping the board in the process is quite powerful
You can also play into an aristocrats strategy, where you sacrifice your own creatures for your benefit, using your Humans as a resource to drain your opponents' life totals without even going to the combat step