A recorded lien that was issued in connection with a court process is certainly worth a lot more than a line in a csv about a debt that is easily challenged and hard to document when challenged.
Liens can be challenged too, but there's a presumption of validity that increases with age, and property sales are hard to do without clearing liens, and challenging a lien seems difficult and time consuming, so it is ignored until a sale is needed with some urgency, chances are the lien will be paid rather than challenged.
I don't have any specific thoughts about wage garnisment, but the % of people that don't get on-the-books wages in the general population may be significantly different from the % in the population that has become the target of debt collection.
Anyway, how many of the debts can be turned into a lien or a garnisment is a question too. You've got to turn the line in the csv into someone you can plausibly sue; and you've got to have upfront capital for the court costs (which probably you can add to the lien, but maybe not?).