It effectively shields your cards from scratches, water damage, and other potential hazards, keeping them in pristine condition
By playing Jim, Space Traveler when you have the RLS Legacy in hand youll have spent five ink to play a four willpower and four health character that quests for two, a four-cost location, spent three ink to move Jim, Space Traveler there, and given Jim, Space Traveler is Evasive for as long as the RLS Legacy remains on the field - thats an absolutely wild amount of value if you can set it up for turn five
It's handy for combo strategies, builds your Storm count, pumps Prowess creatures, puts an Instant into the graveyard to get you towards Delirium or enlarge a Tarmogoyf, and gets you closer to Threshold or pays for Delve costs And sometimes you would rather have cards on top of your deck than in your hand
The other interesting thing is that each Commander deck has a special card called a, you guessed it, Commander who the deck is built around to take advantage of their abilities