Yeah, this is the career-protecting diplomacy of the paper. What it really means is that computation is physical. You have to represent your parameters physically. QC dreams require representing parameters beyond the information capacity of matter. aka below planck scale. Just because you can describe infinite scaling in abstract formulae, doesn't mean you can physically compute that way. Finite information fits in matter and the hard ceiling is Planck. Negative proof is a silly standard, but I understand why the authors are afraid to be direct.