This previous post by Gregory Lewis also seems relevant both to this point in particular, and to this post in general. E.g., Lewis writes:
there is a common pattern of thought along the lines of, āX-risk reduction only matters if the total view is true, and if one holds a different view one should basically discount itā. Although rough, this cost-effectiveness guestimate suggests this is mistaken. Although it seems unlikely x-risk reduction is the best buy from the lights of a person-affecting view (we should be suspicious if it were), given ~$10000 per life year compares unfavourably to best global health interventions, it is still a good buy: it compares favourably to marginal cost effectiveness for rich country healthcare spending, for example.
Second, although it seems unlikely that x-risk reduction would be the best buy by the lights of a person affecting view, this would not be wildly outlandish. Those with a person-affecting view who think x-risk is particularly likely, or that the cause area has easier wins available than implied in the model, might find the best opportunities to make a difference. It may therefore supply reason for those with such views to investigate the factual matters in greater depth, rather than ruling it out based on their moral commitments.
This previous post by Gregory Lewis also seems relevant both to this point in particular, and to this post in general. E.g., Lewis writes: