I would avoid using this feature! It downloads a compiled portable python binary from some random github project not from PSF. That very same github project recommends against using their binary as the compilation flags is set for portability against performance. See https://gregoryszorc.com/docs/python-build-standalone/main/
https://github.com/astral-sh/python-build-standalone is by the same people as uv, so it's hardly random. The releases there include ones with profile-guided optimisation and link time optimisation [1], which are used by default for some platforms and Python versions (and work seems underway to make them usable for all [2]). I don't see any recommendation against using their binaries or mention of optimising for portability at the cost of performance on the page you link or the pages linked from it that I've looked at.
My understanding is that the problem is that psf doesnt publish portable python binaries (I dont think they even publish any binaries for linux). Luckily theres some work being done on a pep for similar functionality from an official source but that will likely take several years. Gregory has praised the attempt and made suggestions based on his experience.
https://discuss.python.org/t/pep-711-pybi-a-standard-format-...
Apparently he had less spare time for open source and since astral had been helping with a lot of the maitinence work on the project he happily transfered over ownership to themin December