Or any philosophy, for that matter. I have been reading up on this subject, "What We Owe The Future" book lately. As I soak up more of the arguments, I see a lot of spilled ink, highly debatable key takeaways, and no practical recommendations for actions which were not already obvious.
In other words, the same thing you will get from any moral philosophy class. If you start philosophy expecting to get something tangibly productive... you are in for a disappointment.
For me, I think the important grain of salt is that better moral accuracy provides little to no value. You or I can do more good for the world with greater effort, but the efficacy of that good is mainly based on the real opportunities which we are connected to through the course of our actual lives. Different moral compasses would give slightly different answers, but the optimization makes a vanishingly thin difference. There was never much doubt about what was needed to be a better person, it's just self-interest and vices, which are completely known quantities, that keeps us from it. The exact flavor of utilitarianism under the hood is pretty much irrelevant.
I do find some value for philosophy as a thought exercise that allows us to entertain radical thought experiments far from the mainstream (see internet trolley cart memes). However, as I see longtermism now, it's pretty vanilla.