I saw a blog calculate that regolith He3 was so sparse that even with a reactor to use it in, one would make more energy from purifying the metals, coil-gunning the purified ingots just past the L1 point so they would fall to Earth, and setting fire to the ingots. Or, entirely separately, by pointing the ingots at electromagnets and collecting the energy from the induced currents from electromagnetic braking.
(I wish I could find the original and link to it. For all I remember it might have been you who wrote it).
(My gut sense is that if aneutronic fusion is practical at all then it'll be cheaper to build more expensive reactors that can run on terrestrial fuels so cheap we use them for car batteries and as an insecticide, rather than slightly less difficult reactors that are fuelled by magic extraterrestrial unicorn sparkle-dust.)