The immense flexibility in when and how often to use their cards lets the sacrifice player shuffle key pieces between zones to dodge almost any removal or potentially beat attempts at disruption while going off by just re-initiating their combo on top of the stack
As a card, it's solid, letting you flood the battlefield with copies of Assassins in exile with memory counters
It also lets you hand out buffs and selectively board wipe which is solid as well
The first time I properly met Simon was at Pro Tour Oath of the Gatewatch, where his team, Team Eureka, broke this deck out into the world after previously only being seen as a fringe deck on Magic Online (funnily enough, the CEO of ThreeForOne, Oliver Polak-Rottman, was also part of Team Eureka!)
It does require subscribing to the Inktable Patreon for the premium version but it can be a good way to practice for in-store Lorcana events