Bathynomus does quite well against a popular killer (MKUltra) and is okay against most breakers on Archives, which could help on maybe 3-4 runs most games. It also fares reasonably well as an early draw against Aumakua decks but produces little value over time against Bukhgalter. If you find yourself frequently needing early Archives protection, which is rare, this is reasonable at $3. Off of archives, it usually has an impact of $0-1 except against MKUltra. Considering how little value ice on Archives usually produce, I think a fair rez price would be closer to $1 for an ice which is only semi-viable on Archives and nowhere else.
How does it do off-Archives?
Most breakers besides MKUltra get through it for $0-1 off-Archives, which is so inexplicably bad for a $3 ice (or even a $0 ice) that rezzing it non-Archives gives the runner useful information about how desperate your draw has been. (On another central server, it suggests your draw has been starved for ice, which reduces the deterrent value of ice for your early game*. A remote Bathynomus suggests a lack of ice or possibly an exotic ZATO). Most other factions shy away from cards which are so bad that using them indicates you are in an existential panic. In Jinteki, you might not have a choice.
Unfrequently asked questions
Why would showing this card off-Archives weaken my position elsewhere? If I've drawn so few ice that I have to rez a Bathynomus off-Archives, I'm showing very low confidence in my ice draw, and the next ice I install will probably be whatever I draw next even if it's situationally terrible. It might be an ice I can't afford yet, a Bran that I don't particularly want to rez right now because it'd bankrupt me for too little short-term value, or a low-impact ice like Aiki on remote. In a situation like this, there's an above-average chance that the corp is not willing or able to rez that ice right now (or that it's unusually low-impact in its position) and that the runner can be more adventurous until they've seen otherwise. In contrast, if I lead with 2-3 ice early or if you access multiple ice from HQ, my installed ice are probably closer to what I was looking for rather than desperation installs.
Is Bathynomus an unusually terrible card? Not compared to most Jinteki cards, arguably. The worst 5 cards in a 2023 Jinteki deck will range from "how did something better NOT get printed?" up to "legit, is our card-pool actually worse than Adam's right now?" Depending on how worried you are that the ice is tied almost exclusively to the least important central server and not even all THAT good at defending it, this feels more like the second than the first.
Why no Aikis on remote? Remote server runs access cards which the corp has already paid to draw and install and also are more likely to be agendas. Aiki doesn't produce enough pain to create scoring windows on remote or adequately protect early assets. If you install a Rashida and they let Aiki fire, you're probably losing more from Rashida getting trashed than they are from Aiki's subroutines. If the run to trash Rashida was on R+D instead, I think you're probably ahead on the exchange with Aiki firing. (You have invested fewer resources into an R+D Rashida than one that you've drawn and installed).
"Doesn't work very efficiently with non-advanceable traps like Snare."
— Cooker