I can only speak for myself, but I take transhumanist formulations seriously because they seem to me to exert a disproportionate and deranging influence on technodevelopmental deliberation at the worst imaginable time.
As I have said, superlative formulations have force because they
[a] activate customary irrational passions that are already occasioned by disruptive technoscientific change (panic from mistaken impotence, greed for mistaken omnipotence), because they
[b] congenially oversimplify and dramatize technodevelopmental complexities (reframing them as transcension, apocalypse, revolution, enhancement, immortalization) for lazy, undercritical, or overwrought people and media formations, because they
[c] conduce to the benefit of incumbent interests that portray themselves as more knowledgeable about matters of "advanced" or "accelerating" developments to justify circumventions of democratic deliberation, or frame technodevelopment in terms of "existential risk" that divert deliberation down corporate-militarist avenues (geoengineering, megascale infrastructure, centralized co-ordinated response).
I can go on, and have done, but I think you get the picture.
The point is, most of the reactionary formations that have menaced late-modernity (extractive-industrial-broadcast epoch) began as marginal subcultures of cocksure white boys certain they had the Keys to History in their hands. The silliness of superlativity is not enough to justify ignoring it or failing to understand it, especially once we see the context of techno-utopianism in which it so legibly locates itself.
I also believe that the Robot Cultists in their very extremity provide unusually distilled illustrations of the associations, dynamisms, guiding figures and so on that also play out in more mainstream neoliberal "globalism" and "development" discourse, and hence put us in a better position to understand the irrationality and authoritarianism of that discourse.
Anyway, as you know from the title of my blog, my hero is the political theorist Hannah Arendt (Amor Mundi, the love of the world, was her personal motto), who insisted that the philosopher's task is understanding, and where politics is concerned this means "thinking what we are doing."
I find that understanding the transhumanists and discerning the ways in which mainstream developmental discourse is illuminated by reference to their extremity helps "think what we are doing" in a moment of unprecedented planetary catastrophe (resource descent, climate change, WMD proliferation), planetary promise (proliferating p2p formations), planetary disruption (the shift into non-normalizing genetic, prosthetic, and cognitive therapies). It's as simple as that.