I don't remember if it was referenced before, IIRC I said it in the thread at some point earlier but the current High Overseer of the Pyramid she's been spending a lot of her time at is childless, loverless, and friendless. He's maintained his position out of sheer ruthlessness, and takes a similar effort as a certain Tyrant of Hag Graef in the future to remain sleepless due to the sheer amount of enemies he has thanks to the sheer wealth and power that being the commander of one of the pyramids can bring him over time. He, therefore, is one of those sorts of bureaucratic entities who is incredibly important, and also is a fault line because if he goes down he has made no bones about having any successors or chosen heirs or the like. His secrets would either die with him, or get released as revenge for his death, that sort of thing. Plenty of lesser overseers would like his position, would certainly say they could do the job as well as him, but whether or not that is true is another thing all together.
So yes, the pyramid is important.
Though, I would caution and say that she is in fact focusing on said pyramid, she's not sprinting across the entire ark setting up bombs at different Tors and Manses. She's been focusing very much on this pyramid that is going to go off and to make it a big enough issue that the people at the Temple of Khaine and the Auction would do the very natural thing of turning to look. And, as a result of the damage to the two previous Aquafarms, damaging one of the pyramids is in turn going to very much accelerate threats, anger, issues, etc. Because it's not even so much the food loss that's as much an issue as the loss of prestige and prominence that losing yet another food source to sabotage that hasn't had the culprits caught yet.
Hultressa has quite heavily alluded to trying to time the bombs to go off so that it fucks over whatever theater and mystique that Alyssa might be trying to conjure at the Auction, and also to force her and others to expend troops to go investigate or otherwise try and lockdown/secure other vital locations/services after a third facility has gone to smoke and/or rubble.
However, at the same time, the explosives going off is already planned to be a thing. How high that meters goes, who might end up drawn away, that is something to consider. But also something to consider is if you want Roland to be present at the Auction. Your wife will have Jaqueline and the rest of the rescued Bretonnian slaves, as well as a pegasus and gryphon that may well be woken up in preparation. But Roland could end up being useful in whatever might happen if you do, in fact, manage to cause significant chaos at the Auction. And, also, Hultressa has made basically no bones about whether or not she's going to be going full bore. She has to. This is her only chance, she believes, and she's been honest about it. But if she has more time spent purely on preparing, that could also have benefits to her preparing things that she otherwise would not have had time for. Bound spells, brewing some potions, this or that, it depends on what this powerful sorceress might be able to do with some prep time.
The choice, however, is yours, as the players.