once a landfall deck gets its engine running, it has no trouble dropping two or three lands in a turn, and the Godmaw converts spells like Reshape the Earth and Cultivator Colossus into immediate kill spells
You need like ten mana before your bigger plays become easier to pull off, so getting there faster, while drawing a card, is a very good use of your early turns
Even the most well-sculpted hand can get ravaged by discard, and this hits two of your cards at random
With turnaround times at major grading services ranging anywhere from a few days to over a year, I didnt want to absorb the risk of buying cards, sending them off to get graded, and then have to watch helplessly as the price point/support that I bought the raw card at get decimated as card values were to fall (and I didnt have my card back from the grading service yet)
Specifically if you can meet them and see the cards in person and they allow you to verify its authenticity or provide you with authenticity verification paperwork