Finally, and most likely, obviously a 600 atk monster is vulnerable to other monsters, it has no flesh, and especially since your opponent can just plop their monster (700 atk or more) in a DIFFERENT zone on their turn and blow it up
The ability to cross cards between grading companies (CGC to PSA, BGS to PSA, etc.) creates additional supply of PSA 10s as people convert their best-graded cards
However, for those seeking specific cards, booster packs might not necessarily be the best option
The first group, the less-supported types, tend to follow a much more cookie-cutter deckbuild and gameplay strategy
But, like the front of the card, the back matters
Animate Dead and Reanimate are cheap to cast and will drag your Commander back for round two if it should end up in the yard