Contents of Allagan Tomestones

[Daralii]

Despite being a lore addict, none of this had occurred to me at all. Now I feel terrible for handing over all my tomes to Rowena for shinies instead of taking them back to my study and writing down all the information on them! And what, by the Twelve, is Rowena doing with them?! Is she amassing all this information with a view to world domination? Will Rowena turn out to be the final boss of FFXIV?! I am very suspicious now ...

Would she even be able to access the data on them? My impression is that they function like USB drives, and would require a terminal with a proper port, possibly multiple terminals depending on whether or not the early-model and late-model tomestones are compatible with the same ports.

[TinyRedLeaf]

^ Rowena has implied in the Stormblood SMN story line that she does, in fact, have the proper terminals and tools to access the data in the tomestones.

Without giving too much away, "something-something" happened, and Y'mhitra and to WoL were advised by Rammbroes of the Sons of Saint Coinach to find more information about the Allagans from Rowena.

Rowena uncharacteristically agreed.

In fact, she offered to lend Y'mhitra the transcripts of what her flunkies had found so far, to save her from the trouble of getting the right equipment to access the tomestones in question, on the condition that Y'mhitra tells her about anything significant she learns. Rowena complained that there's too much data, and she doesn't have all the time in the world to browse ancient history.

[Anonymoose]

More specifically, she seems to have a certain symbiotic relationship with the Garland Ironworks:

Well, I suppose it wouldn't hurt to lend you some o' my tomestones. In fact, I'll do you one better and let you borrow the transcripts─courtesy o' the scribes at the Ironworks. As books, they're a damn sight heavier, but you don't need fancy machines when it's all penned down in ink and parchment. Give me a summary of the contents when you're finished, and I'll consider that as payment. Collectors'll part with more coin if they know what they're gettin', and my time's too precious to waste on readin' ancient history!

[Rongway]

And what, by the Twelve, is Rowena doing with them?! Is she amassing all this information with a view to world domination? Will Rowena turn out to be the final boss of FFXIV?! I am very suspicious now ...

We sell the tomestones to Rowena for things (yes, to us it looks like we're buying gear with tomestones, but from her perspective, she's buying our tomestones for dirt cheap). She eventually sells the tomestones to rich third parties who have tomestone readers. Given the various types of tomestones available, her end clientele are probably varied as well. Historical records might be absurdly valuable to one, while another might be interested strictly in artistic literature. But whatever type of knowledge the different tomestones contain, there's sure to be some rich person somewhere who'll pay out the arse for those tomestones, and Rowena is going to capitalize where she can.

[koichi88]

Some assumptions/headcanon:
While the name of the tomestone denotes what general category it's contents fall under each tomestone is not necessarily unique in it's contents. A lot of what we're handing over is probably duplicate data, but Rowena doesn't know for sure and is willing to risk it.
Eventually Rowena amasses so many duplicates (as identified by the Ironworks) that she no longer feels it is worthwhile to collect a particular kind of tomestone, reasoning that shes got just about everything from that category.
At this point does one last going out of style sale and collects whatever anyone has left in exchange for older tomestones that might still contain something of value in a bid to grab whatever missing data might still be out there.
Esoteric Tomestone contain ancient Allagan memes/ personal information not widely distributed.
Lost Allagan gear was created based on a design found within the tomestones, intended for front line fighters and extrapolated for casters and such. Rowena is unaware that the design was just a concept piece created by an Allagan artist. Jessie is very much aware.

[YianKutku]

Esoteric Tomestone contain ancient Allagan memes

You have my attention.

[Shadotterdan]

Isn't it implied that the ironworks, and primal gear were developed based on information from the tomestones?