This gets cited here weekly, usually second-hand, so it is worth setting out what it does and does not establish.
The trade-off is reversibility against privacy and there is no option that gives you both. Card payments are reversible and disclose the most; crypto discloses least and is irreversible, which is precisely why pressure toward it is a warning sign when it comes from a seller rather than a buyer. Escrow only means anything where the escrow agent is independent of both parties, which is rarely the case in practice.
Where I think it is weakest: the follow-up is short relative to how long people actually take these drugs, so durability is an assumption here rather than a finding.
What I actually want to know is how people are thinking about the trade-off between reversibility and privacy, because you cannot have both. Tell me what I have not thought of.
Note on sourcing:
Figures above are from the primary publication rather than the press summary. If a number here disagrees with one you have, post yours and we will work out which of us is reading a secondary source.