In it, the Phyrexians simultaneously invaded almost every plane in the Multiverse, including Eldraine
If your commander would die, you can whisk it right back to the command zone instead, where it's ready to be cast again
Devoted Druid / Vizier of Remedies combo decks were already degenerate, even by Modern standards
The nice part is that youre already attacking with a bunch of samurai to capitalize on the bonus, and most of them have bushido if theyre blocked, so its not going to end well for your opponent
One consideration: BGS cases have been known to have a tiny bit of inner card movement if shaken (especially if the card is thin), but generally they use inner sleeves to help with this
Hall of Gemstones is incredibly disruptive for most decks with two or more colors and will force your opponents to be very careful about how they use their mana rocks