I agree with your points. I don't think any leftist party can officially have accelerationism as part of their platform for obvious publicity reasons to the uninitiated. However, I can't really see how it hurts for USians to privately root for it by sucking money out of the USA and pumping it into the Global South.
Firstly, we in the USA unfortunately have a very limited timeline at this point to win the revolution. There are only two permanent ways to resolve the class contradiction. Either the workers get rid of the capitalists, or the capitalists kill all the workers and replace them with robots.^[https://www.versobooks.com/products/59-four-futures] This is why Sam Altman and co. are so excited about AI.
In less than 100 years, the US capitalists will probably have AIed and automated everything, from AI production chains to robot cops. They will never need a human worker to touch shit again, and there is nothing said worker can do about it. There is nothing a worker can do to fight against robot terminator cops. It will allow capitalists to genocide, or mentally lobotomize, the former 'working' masses who are now nothing more than a nuisance, unwanted livestock.
To anyone who thinks that this is far-fetched, they are sorely misguided. Peter Thiel and co. are already talking about this future:
People who are not 'productive' would best be converted to biodiesel. Barring that, "our goal, in short, is a humane alternative to genocide. That is: the ideal solution achieves the same result as mass murder (the removal of undesirable elements from society), but without any of the moral stigma."
"The best humane alternative to genocide"...is "to virtualize them. A virtualized human is in permanent solitary confinement, waxed like a bee larva into a cell which is sealed except for emergencies. This would drive him insane, except that the cell contains an immersive virtual-reality interface which allows him to experience a rich, fulfilling life in a completely imaginary world."
— Curtis Yarvin, with approval/following from Peter Thiel, JD Vance, Marc Andreessen ^[https://newrepublic.com/article/183971/jd-vance-weird-terrifying-techno-authoritarian-ideas] ^[https://www.unqualified-reservations.org/2008/11/patchwork-2-profit-strategies-for-our/]
Secondly, against this timeline, it is imperative for U.S. Socialist parties to organize as hard as they possibly can. As conditions deteriorate for Americans, we can expect these parties to grow in popularity. However, what we need to avoid along the way is for the US bourgeoisie to not be rabid enough, to freak out from the socialist organizing, and add back enough social safety nets FDR-style to get people to go back to sleep, just to finish the full robotization and then kill us all off.
We sort of need the bourgeoisie to walk a fine line. We want them to respond somewhat to socialist parties' demands, so that socialists can get small wins to use to further organize, but never wins big enough to demobilize the working class, and to always have a creeping line of oppression that we can mobilize further against.
Thirdly, the US Empire survives to this day only because the Global South is still mostly weak as fuck and has no money and no power. Out of the entire globe, the U.S. is the country with the most colonially-stolen money. So if any accelerationist can take money out of the U.S. and pump it in to the Global South, that is strictly a net benefit.
Based on these conditions, if a so-called accelerationist and socialist sympathizer wants to deliberately drain money out of Americans and pump it into the Global South, there is nothing wrong with that. They just need to regulate the amount of extraction such that it maintains the necessary creeping rate of oppression. This means ramping up exploitation when other capitalists want to give back concessions, and ramping it down when things are deteriorating too fast for good organizing to take place. That way they can play the bad cop to socialist good cop and hopefully drive stuff towards a better end.
If I somehow do end up getting a fuck ton of money in the US, and the socialist parties are still falling behind, my goal will be to use the money to further drain as much money from Americans as possible and shuttle it to China or whatever other promising Global South or AES states. Even if the USA becomes a capitalist wasteland, at least the Global South will be developed enough to ignore the dying Americans.