Prison/stax decks stop your opponent from playing cards and attacking you while gaining incremental advantages over time, be it with lifegain, Treasure tokens, or card draw
In fact, this is a cornerstone of equipment-based strategies
Each deck comes with ten new-to- Magic cards, the face card and another powerful legendary creature each in traditional foil, plus the foil-etched display commander
The games where Venser doesnt feel good enough tend to involve the opponents ability to replay the card youre trying to bounce and you not having a permanent answer to the card
Flexibility is always good, though
I have had it often enough where I am able to play the Gem with one or no lands in play, I have even cast it simply as a way to relay my Tolarian Academy so that I could tap it again for substantially more than the four mana used to play the Gem with