From the announcement:
Why online lists?
Inevitably, as we expand our Antarean ranges the original army lists become out of date. As we publish more supplements, the relevant army lists entries become dispersed over a series of publications. It’s very inconvenient! By making the army lists available online we can ensure the current version is there for all to download. Did we mention they’re Free?
Another useful thing about having our lists online is that we can make any necessary corrections or amendments quite quickly. That might mean addressing a genuine mistake – though hopefully not too often. More likely it will reflect community feedback, allowing us to fine tune a rule or value, or change the expression of an entry to make things clearer.
Lastly, an online list provides more space to present the lists, which means we can add pages as needed and include more by way of explanation where it is useful to do so.