I agree.
Activities such as PI or skill farming are indeed reliable, but they are not linearly time scaled nor hourly repeatable, so they do not naturally fit into a strictly hourly metric. In these cases, GPH is less meaningful at the session level and more appropriate at the cycle level (for example weekly or monthly). In other words, total realized income over the full cycle relative to the actual time invested across that entire process.
Especially with activities like PI, production itself is only one part of the time investment. There is also time spent on management, collection, hauling, processing or transforming the output, transporting to a trade hub, placing sell orders, possible relisting, and the waiting period until liquidation. All of these are part of the real time that is effectively “locked” before the income is realized, and they are not well captured by a simple hourly session metric.
In essence, my intention is not to strictly model passive or time-decoupled income sources in an hourly sense, but rather activities where time is more directly and repeatedly converted into production (such as mining, ratting, exploration, etc.). For PI, skill farming, or other periodic income streams, it works better as a “side” baseline within an overall income “portfolio,” evaluated over a longer time cycle that also includes hauling, selling, and market handling.
Therefore, I would say is most useful for comparing active and repeatable activities and for making the opportunity cost of time more visible, while passive and periodic incomes are more accurately assessed on a longer, cycle-based horizon rather than a strictly hourly session basis.