This is the same as how a different Karn, Scion of Urza, can grab a card exiled from a previous one
It excels in Commander, which encourages you to play creatures large enough that this is mana neutral because somebody at Wizards thought that would be an okay ceiling and games go long enough to really milk the card advantage
At the time of writing, both TCGPlayer and eBay sales show the card with listings for around $1,600 or higher
This includes dropping the price on Masters set packs back down to $7, reprinting more cards that are expensive because they have a lot of demand (rather than cards like Imperial Recruiter that were expensive because they were low in supply), and refocusing reprint efforts to popular formats like Modern (either by bringing back Modern Masters or by making sure that themed Masters sets are stocked with expensive Modern staples)
Once you flip Venat and again this will be easier in GW, with it costing (7) you get to exile something and get an even better card draw machine that can save something from board wipes until your next turn