Still we should recall the utility gained in using the right tool is finite and variable. In some cases can be like night and day while in other cases a moderate or negligble improvement might be all you see. Under some circumstances familiarity with a given tool may outweigh the advantages of using a better suited tool - especially if a team lacks well-rounded expertise.
Reinforcing the other side of the argument is the fact that programmers are often subject to constraints placed on them from on high that restrict the choices they might make in such.
Given the specific situation, the author seems to build a pretty good case for SQLite at least by my own limited understanding of the facts.